Method of producing crystal bodies having controlled crystalline orientation

ABSTRACT

This invention lies in that a seed material controlled into a predetermined orientation is joined to a treating material under an activated state of joint face or through an interposition of an insert member and heated to a temperature causing grain boundary movement to render a whole of a joined body into a crystal body having a predetermined crystalline orientation. Furthermore, not only plate material and bar material but also coil can be used as the treating material, so that crystal bodies having excellent desired properties can be mass-produced with a good yield and in industrial scale.

TECHNICAL FIELD

This invention relates to a method of producing a crystal body having acontrolled crystalline orientation, and more particularly to a method ofproducing crystal bodies having a predetermined orientation such assingle metal crystal, grain oriented silicon steel sheet, bidirectionaloriented silicon steel sheet and the like wherein the crystal bodyhaving the predetermined orientation is rapidly and simply produced byartificially planting a seed crystal of an adequate orientationirrespective of the size of the crystal body and hence the massproduction can be made in industrial scale.

BACKGROUND ART

There are basically four known methods for obtaining crystal bodieshaving a desirable orientation.

(1) First, the simplest method is a method wherein a block-like singlecrystal is prepared and then a crystal body is cut out therefrom in adesired orientation in accordance with the measured result of singlecrystalline orientation.

In this method, however, the cutting takes a long time, the cost ishigh, and also the size of the single crystal to be prepared iscritical. Therefore, the mass production can not be expected.

(2) Second, there is a so-called strain-slant annealing method. Thismethod is a method of growing a single crystal of desirable orientationfrom an end of a sample, wherein a seed crystal is first prepared on theend of the sample and rotated in a desired direction to grow the wholeof the seed crystal into a single crystal having the desirableorientation, and has been proposed by Fujiwara et al [T. Fujiwara and T.Hudita; J. Sci. Hiroshima Univ. A8 (1938), P293˜296].

They have succeeded in the preparation of single crystals by the abovemethod from aluminum and further from pure iron.

Thereafter, Dunn et all have applied the above method to silicon steelsheets having a large size [C. G. Dunn and G. C. Nonken: Metal Progress,64 (1953) 6, P71˜75].

According to their method for growing a plate crystal having a specifiedcrystalline orientation, an end of a sample previously subjected to astrain is placed in a high temperature region of a temperature tiltingfurnace to prepare some seed crystals as shown in FIG. 1a, among which acrystal grain having an adequate orientation is selected and cut out asshown in FIG. 1b. Then, a necked portion of the cut out crystal grain isbent as shown in FIGS. 1c and 1d to align the seed crystal into apredetermined orientation with respect to the sample plate. Next, theseed crystal is annealed through heating in the temperature tiltingfurnace so as to grow over the whole of the plate, whereby the object isachieved.

In this method, however, it is necessary to strictly control theoperation for selecting and cutting out a seed crystal having anadequate orientation from many crystal groups and the operation forbending the seed crystal into a predetermined orientation, which takesmuch labor and long time, so that the mass production can not beexpected.

(3) Third, there is a method utilizing secondary recrystallizationphenomenon.

The secondary recrystallization is a phenomenon that a seed ofnucleating secondary grains largely grows through grain boundary energyof primary recrystallized grains as a driving force, which is widelyutilized as a method of producing grain oriented silicon steel sheets asis well-known.

The grain oriented silicon steel sheet is required to have excellentmagnetic properties in the rolling direction. That is, it is requiredthat as the magnetizing force (magnetized properties), the magnetic fluxdensity represented by B₁₀ value (magnetic flux density in the rollingdirection produced when the magnetizing force is 1000A /m) is high andthe iron loss represented by W_(17/50), value (iron loss when beingmagnetized at a magnetic flux density of 1.7 T and a frequency of 50 Hz)is low so that it is fundamentally necessary to highly align <001> axisof secondary recrystallized grains in steel into the rolling direction.For this end, fine precipitates such as MnS, MnSe and the like aregenerally added as an inhibitor, and further, if necessary, a smallamount of Sb as disclosed in Japanese Patent Application Publication No.51-13469, a small amount of Mo as disclosed in Japanese PatentApplication Publication No. 57-14737 or a combination of Al, N, Sn, Cuand the like as disclosed in Japanese Patent Application Publication No.60-48886 is added, which are properly combined with treating conditionsin each of hot rolling and cold rolling, whereby high magnetic fluxdensity and low iron loss grain oriented silicon steel sheets having aB₁₀ value of magnetic flux density of more than 1.90 T and a W_(17/50)value of iron loss of not more than 1.05 W/kg (thickness 0.30 mm) havebeen produced recently.

Furthermore, a technique of producing bidirectional oriented siliconsteel sheets by crossly conducting the cold rolling is proposed inJapanese Patent Application Publication No. 35-2657 and the like.

However, in order to highly align <001> axis of secondary recrystallizedgrains in the product into the rolling direction or a directionperpendicular to the rolling direction, it is necessary to adjust thecomponents and strictly control complicated and many steps ofsteel-making, hot rolling, cold rolling and heat treatment. In theactually industrial production, however, the treating conditions are aptto be shifted from the totally proper conditions as mentioned above. Ifthe treating conditions are slightly shifted, there is caused a problemthat the orientation of <001> axis into the rolling direction or thedirection perpendicular to the rolling direction becomes poor.

Lately, it has been attempted to thin the thickness of product plate toreduce the iron loss. However, as the final thickness becomes thin, thealignment of <001> axis of secondary recrystallized grains into therolling direction or the direction perpendicular to the rollingdirection becomes unstable, so that the improvement thereof is stronglydemanded.

In Japanese Patent Application Publication No. 58-50295 is disclosed amethod utilizing the same method as described in the item (2), whereinsecondary grains locally subjected to secondary recrystallization areused as a seed and a temperature gradient is applied to a steel sheet ata boundary between primary and secondary recrystallization regions togrow the seed. However, the production as a commercial material is notyet attained at the present.

As a basic problem, the resulting crystalline orientation range isrestricted in the aforementioned secondary recrystallization method, andconsequently there is a problem that the orientation largely shiftedfrom (110)[001] orientation or (100)[001] orientation is not obtained.

(4) Fourth, there is a method utilizing third order recrystallization.

The third order recrystallization proceeds through surface energy as adriving force, which is utilized for mainly growing (100)[hkl] grains inbidirectional oriented silicon steel sheet or the like, but there areproblems on atmosphere control at high temperature, accuracy oforientation control and the like.

As mentioned above, the mass production can not be achieved in themethod capable of strictly controlling to a specified orientation, whilethe orientation selectivity and control accuracy come into problem inthe method capable of industrially conducting the mass production, sothat methods capable of conducting the mass production and strictlycontrolling to the specified orientation are not yet known up to thepresent.

Moreover, the production of single crystals through solidificationmethod wherein a seed crystal is planted on an end of molten liquidmetal and gradually cooled below the melting point to grow the seedcrystal into a large crystal is known as a Bridgeman method or aTanmann-Bridgeman method from the old time. However, the invention is atechnique that a treating material growing the seed material is notliquid but is a solid having a crystal structure, and is entirelydifferent from the aforementioned solidification method.

As mentioned above, if it is intended to strictly control the crystalinto the specified orientation, much labor and long time are taken forobtaining a proper seed, so that the mass production can not beconducted industrially. On the other hand, if it is intended to conductthe mass production, the seed is necessary to be prepared by rolling andrecrystallization, so that there is caused a problem on the accuracy ofcontrolling to the specified orientation due to the scattering ofproduction conditions. Furthermore, the growing orientation isrestricted from a viewpoint of the essential crystal structure of thestarting material, so that there is remaining a problem that theorientation can not be selected.

In this connection, the inventors have already found a method ofdirectly planting a previously and strictly controlled seed crystal on asteel sheet through welding as a method of preparing nucleus ofsecondary recrystallized grains without rolling and recrystallization inthe production of grain oriented silicon steel sheets and disclosed inJapanese Patent laid open No. 63-149318.

In this method, however, the quality of joint portion is changed by theheat affection in the welding, so that there is remaining a problem thatit is very difficult to preferentially grow the planted secondary grainnucleus stably over the weld portion.

DISCLOSURE OF INVENTION

The invention is to advantageously solve the aforementioned problems andto provide a method of producing crystal bodies having a strictlycontrolled crystalline orientation which can realize both theindustrially mass production and the strict orientation control to aspecified crystalline orientation.

Further, the invention is to more improve the iron loss properties bypositively shifting <001> axis of Goss grains from the rolling face incase of producing the grain oriented silicon steel sheet.

That is, in order to improve the iron loss properties, it is favorablethat <001> axis of the Goss grain is not completely coincident with therolling face and is somewhat shifted therefrom, which is described, forexample, in Japanese Patent Application Publication No. 57-61102 and[IEEE. Transactions on Magnetics Vol. Mag 21. No. 1 (1985)].Particularly, as to |β|, about 2.5° is optimum for the reduction of ironloss, so that the orientation alignment near to β=2.5° is stronglydemanded. In the conventional method through rolling andrecrystallization, if it is intended to raise the degree of aligninginto {110}<001> orientation, |β| among |α|, |β| and |γ| is particularlyeasy to be aligned near to 0. Therefore, in order to control theorientation near to β=2.5°, as disclosed in Japanese Patent ApplicationPublication No. 58-5969, there is adopted a nonproductive method whereinwaves are formed on a cold rolled steel sheet in a direction crossingwith the cold rolling direction, and the waved steel sheet is subjectedto a decarburization annealing and further to a secondaryrecrystallization annealing in a continuous strip system, and then thesheet after the coating with a slurry of an annealing separator issubjected to a purification annealing in a box and further to acorrecting treatment for flattening the waves on the waved sheet.

Now, the inventors have previously noticed the method of planting a seedand made various proposals on the method of planting seed crystalthrough welding. In these proposals, however, there is a problem thatthe seed can not stably ride over the weld portion due to the heataffection in the welding as previously mentioned.

Therefore, the inventors have made further studies on the joining methodlessening the heat affection as far as possible and found out aneffective means for achieving essential matters required in lowtemperature joining, that is:

1) impurities are small in the joint face;

2) the joint face is approached as far as possible.

Furthermore, it has been found that when utilizing such a lowtemperature joining method, the steel sheet itself as a treatingmaterial is not necessary to be subjected to the strict orientationcontrol as in the conventional method and hence the orientation of theseed material is strictly controlled to grow the orientation of the seedmaterial over the whole region of the steel sheet, whereby theproperties equal to or more than those of the conventional case throughthe complicated steps are obtained.

The invention is based on the above knowledge.

That is, the invention is as follows:

1. A method of producing crystal bodies, characterized in that a seedmaterial having a crystal structure same as or similar to that of atreating material and a predetermined crystalline orientation at a stateof energy lower than that of the treating material is joined to thetreating material under such a contact state that a joint face isactivated, and then heated to a temperature causing grain boundarymovement to render a whole of a joined body into a crystal body havingthe predetermined crystalline orientation (first embodiment of theinvention).

2. A method of producing grain oriented electromagnetic steel sheetshaving improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a finishannealing, characterized in that a recrystallization seed material isjoined on an edge portion of the steel sheet as a treating material at astep after the hot rolling and before the finish annealing under acondition satisfying the following orientation relationships, in which ajoint face is activated at a contact state, and then heated to atemperature causing grain boundary movement to grow the orientation ofsaid seed material over a whole of said steel sheet (second embodimentof the invention).

    Account

    |α|≦5°

    1≦|β|≦5°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of <001> axis of seed material with respect torolling face of steel sheet.

3. A method of producing grain oriented electromagnetic steel sheetshaving improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a primaryrecrystallization annealing and further to a finish annealing,characterized in that a recrystallization seed material is joined on anedge portion of the steel sheet as a treating material at a step afterthe hot rolling and before the finish annealing under a conditionsatisfying the following orientation relationships, in which a jointface is activated at a contact state, and then heated to a temperaturecausing grain boundary movement to grow the orientation of said seedmaterial over a whole of said steel sheet (third embodiment of theinvention).

    Account

    |α|≦5°

    1≦|β|≦5°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of <001> axis of seed material with respect torolling face of steel sheet.

4. A method of producing grain oriented electromagnetic steel sheetshaving improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a finishannealing, characterized in that a recrystallization seed material isjoined on an edge portion of the steel sheet as a treating material at astep after the hot rolling and before the finish annealing under acondition satisfying the following orientation relationships, in which ajoint face is activated at a contact state, and then heated to atemperature causing grain boundary movement to grow the orientation ofsaid seed material over a whole of said steel sheet (fourth embodimentof the invention).

    Account

    |α|≦10°

    |β|≦10°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of {100} face of seed material with respect torolling face of steel sheet.

5. A method of producing bidirectional oriented electromagnetic steelsheets having improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a primaryrecrystallization annealing and further to a finish annealing,characterized in that a recrystallization seed material is joined on anedge portion of the steel sheet as a treating material at a step afterthe hot rolling and before the finish annealing under a conditionsatisfying the following orientation relationships, in which a jointface is activated at a contact state, and then heated to a temperaturecausing grain boundary movement to grow the orientation of said seedmaterial over a whole of said steel sheet (fifth embodiment of theinvention).

    Account

    |α|≦10°

    |β|≦10°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of {100} face of seed material with respect torolling face of steel sheet.

6. A method of producing orientation controlled steel sheets in thefirst, second, third, fourth or fifth invention, characterized in that acoil-like steel sheet is used as a treating material, and a seedmaterial having a crystal structure same as or similar to that of saidtreating material and a predetermined crystalline orientation at a stateof energy lower than that of said treating material is contacted andjoined with a coiled end face of said coil-like steel sheet, and thenheated to a temperature causing grain boundary movement to render saidcoil-like steel sheet into a crystal body having the predeterminedcrystalline orientation (sixth embodiment of the invention).

7. A method of producing crystal bodies, characterized in that a seedmaterial having a crystal structure same as or similar to that of atreating material and a predetermined crystalline orientation at a stateof energy lower than that of the treating material is joined to thetreating material through an insert member having a melting point lowerthan those of the seed material and the treating material, and thenheated to a temperature causing grain boundary movement to render awhole of a joined body into a crystal body having the predeterminedcrystalline orientation (seventh embodiment of the invention).

8. A method of producing grain oriented electromagnetic steel sheetshaving improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a finishannealing, characterized in that a recrystallization seed material isjoined on an edge portion of the steel sheet as a treating material at astep after the hot rolling and before the finish annealing under acondition satisfying the following orientation relationships, in whichsaid seed material is contacted with said steel sheet through an insertmember having a melting point lower than those of said seed material andsteel sheet, and then heated to a temperature causing grain boundarymovement to grow the orientation of said seed material over a whole ofsaid steel sheet (eighth embodiment of the invention).

    Account

    |α|≦5°

    1≦|β|≦5°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of <001> axis of seed material with respect torolling face of steel sheet.

9. A method of producing grain oriented electromagnetic steel sheetshaving improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a primaryrecrystallization annealing and further to a finish annealing,characterized in that a recrystallization seed material is joined on anedge portion of the steel sheet as a treating material at a step afterthe hot rolling and before the finish annealing under a conditionsatisfying the following orientation relationships, in which said seedmaterial is contacted with said steel sheet through an insert memberhaving a melting point lower than those of said seed material and steelsheet, and then heated to a temperature causing grain boundary movementto grow the orientation of said seed material over a whole of said steelsheet (ninth embodiment of the invention).

    Account

    |α|≦5°

    1≦|β|≦5°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of <001> axis of seed material with respect torolling face of steel sheet.

10. A method of producing bidirectional oriented electromagnetic steelsheets having improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a finishannealing, characterized in that a recrystallization seed material isjoined on an edge portion of the steel sheet as a treating material at astep after the hot rolling and before the finish annealing under acondition satisfying the following orientation relationships, in whichsaid seed material is contacted with said steel sheet through an insertmember having a melting point lower than those of said seed material andsteel sheet, and then heated to a temperature causing grain boundarymovement to grow the orientation of said seed material over a whole ofsaid steel sheet (tenth embodiment of the invention).

    Account

    |α|≦10°

|β|≦10°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of {100} face of seed material with respect torolling face of steel sheet.

11. A method of producing bidirectional oriented electromagnetic steelsheets having improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into a finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a finishannealing, characterized in that a primary recrystallization annealingand further to a finish annealing characterized in that arecrystallization seed material is joined on an edge portion of thesteel sheet as a treating material at a step after the hot rolling andbefore the finish annealing under a condition satisfying the followingorientation relationships, in which said seed material is contacted withsaid steel sheet through an insert member having a melting point lowerthan those of said seed material and steel sheet, and then heated to atemperature causing grain boundary movement to grow the orientation ofsaid seed material over a whole of said steel sheet (eleventh embodimentof the invention).

    Account

    |α|≦10°

|β|≦10°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of {100} face of seed material with respect torolling face of steel sheet.

12. A method of producing orientation controlled steel sheets in theseventh, eighth, ninth, tenth or eleventh invention, characterized inthat a coil-like steel sheet is used as a treating material, and a seedmaterial having a crystal structure same as or similar to that of saidtreating material and a predetermined crystalline orientation at a stateof energy lower than that of said treating material is contacted andjoined with a coiled end face of said coil-like steel sheet through aninsert member having a melting point lower than those of said seedmaterial and said treating material, and then heated to a temperaturecausing grain boundary movement to render said coil-like steel sheetinto a crystal body having the predetermined crystalline orientation(twelfth embodiment of the invention).

In each of the above embodiments of the invention, the joining betweenthe treating material and the seed material is preferable to be carriedout under an application of stress.

Furthermore, in each of the above embodiments of the invention theheating atmosphere is favorable to be a non-oxidizing atmosphere.

In the production methods of grain oriented electromagnetic steel sheetsin the second, third, eighth and ninth embodiments of the invention andbidirectional oriented electromagnetic steel sheets in the fourth,fifth, tenth and eleventh embodiments of the invention, it is desirableto reduce C amount in steel before cold rolling to not more than 0.010wt % (hereinafter shown simply by %).

The term "same crystal structure" used herein means a structure thatcrystal system and lattice constant are same, and the term "similarcrystal structure" means a structure in which an interstitial or asubstitution type element is included as an alloying element and thecrystal lattice is disordered due to solid solution, regular latticeformation, precipitation and the like. In this case, it is preferablethat the difference of crystal lattices is within 30%.

Moreover, the term "energy state" used in the invention is concernedwith inner strain and surface and is mainly dependent upon quantity andmass of crystal grain boundary, dislocation, point defect and surfaceenergy of crystal. As these quantities increase, the energy statebecomes higher.

Then, each of the inventions will be described concretely based on basicexperiments leading in the success of each invention.

AS TO THE FIRST AND SEVENTH EMBODIMENTS OF THE INVENTION Experiment 1

As a seed material A at a low energy state, there was provided a singlecrystal plate comprising Si: 3% and the balance being substantially Feand having (110) face in its plate surface and a thickness of 0.3 mm anda square of 10 mm, while as a treating material B at a high energystate, there was provided a steel sheet of 10 mm square obtained by hotrolling an ingot of silicon steel comprising Si: 3%, S: 0.020%, Al:0.025% and N: 0.0080% and the balance being substantially Fe and coldrolling it to a thickness of 0.3 mm and cutting out therefrom.

Two plate surfaces of each of A and B were finished into a mirror statehaving a center-line average roughness Ra of not more than 0.01 μmthrough Emery polishing, buff polishing or float polishing.

These polished surfaces of A, B were subjected to an ion sputtering ofAr under a high vacuum of 10⁻⁶ Torr, and thereafter mirror surfaces ofA, B were contacted with each other to form two joined bodies C and D.

The annealing at 1000° C. for 5 hours was applied to the body C under asuperhigh vacuum of 10⁻¹⁰ Torr and to the body D in N₂, respectively.

As a result, the grain boundary locally remained in the joint face ofthe body D. Further, when the crystalline orientation of A, B includingthe joint face was measured, portions restraining the grain boundary inthe joint face had different orientations, and the portions having nograin boundary had the same orientation.

On the other hand, no grain boundary was recognized in the joint face ofthe body C, so that when the crystalline orientation of A, B includingthe joint face, the same orientation was observed, and consequently Bwas a single crystal body having the same orientation as in A.

That is, the material A having a crystal structure at low energy statewas joined with the material B having a crystal structure at high energystate through the heating by controlling the atmosphere in the heatingso as not to form an impurity film at the joint face between both thematerials A and B, whereby the amount of the material A having thecrystal structure at low energy state could be increased to two times.

In order to advantageously proceed the industrial production with thedecrease of the cost, the atmosphere in the above heating is convenientto be non-oxidizing gas (N₂ or Ar) atmosphere rather than vacuum. Thispoint was solved by joining the joint surface through a low meltingpoint metal as mentioned below.

That is, each of the above seed material A and the treating material Bwas subjected to a plate surface treatment of each of

i) pickling with hydrochloric acid;

ii) grinding;

iii) Emery polishing;

iv) chemical polishing;

v) chemical polishing+ion etching

and then the treated surface was subjected to Sn plating at a thicknessof 0.5 μm. Then, Sn plated surfaces were contacted with each other as aset of A and B and annealed in N₂ atmosphere at 1000° C. for 10 hours byvarying stress vertically applied to the contacted surface every theplate surface treating condition, and thereafter the presence (x) andabsence (O) of crystal grain boundary at the joint interface wasobserved.

The results are shown in FIG. 2.

As seen from the results of this figure, in the pickling treatment withhydrochloric acid making the roughness large and retaining manyimpurities on the surface, the strong applied load was required fordisappearing the crystal grain boundary, while in case of chemicalpolishing+ion etching making the surface smooth and reducing impurities,the crystal grain boundary could be disappeared without the applicationof load.

Thus, the feature that Sn film having a melting point as low as 232° C.is interposed to disappear the crystal grain boundary is considered tobe due to the fact that the liquid Sn is closely filled in the jointinterface in the heating to shut off from air at a relatively lowtemperature, whereby the influence of the atmosphere is removed toprevent the formation of impurity film. Such an effect of disappearingthe crystal grain boundary becomes large as the surface roughness of thejoint face is small or the applied load is large. This is considered tobe due to the fact that as the surface roughness becomes small or theapplied load becomes large, the contact area increases and also extra Snamount remaining in gaps at the interface becomes small to make easy themovement of crystal grain boundary at the joint face, while theinterface becomes active through the increase of dislocation, slidedeformation and the like by the increase of stress and consequently thediffusion and dilution of Sn, which naturally obstructs the grainboundary movement, into the seed material and the treating material iseasy and the contact area of the active surface increases.

From the above experimental results, it has been found out that thesubstance having the predetermined crystalline orientation can easily beproduced by heating with the holding of the activated state or throughthe low melting point metal.

Then, these invention methods will concretely be described in the orderof production steps.

At first, it is desirable that the treating material and the seedmaterial have the same crystal system such as fcc, bcc or the like as tothe crystal structure, and further it is preferable that the latticeconstant has no great difference.

Furthermore, in the treating material and the seed material, (i) kindand quantity of impurity contained in the material, (ii) kind andquantity of element added, (iii) recrystallization texture, and (iv)quantity and mass of crystal grain boundary included, dislocation, pointdefect and surface energy and the like are not particularly definedbecause they are different in accordance with each substance orproduction step. However, it is important that energy state of thetreating material is higher than that of the seed material. Because,when the energy state of the seed material is equal to or higher thanthat of the treating material, the seed material can not grow to achievethe given object.

If the energy state of the treating material is too high, a nucleus ofunsuitable orientation different from that of the seed material iscreated in the treating material and finally the given object can not beachieved, so that the energy state is necessary to be adjusted to aproper height in accordance with each case.

Moreover, the shape of these materials may be block, plate, line, grainand the like and are not particularly restricted. For example, in caseof producing the grain oriented silicon steel sheet, bidirectionaloriented silicon steel sheet and the like, cold rolled coil obtainedaccording to the usual manner as well as rapidly quenched ribbonobtained by roll quenching method and the like are advantageouslyadapted as the treating material.

Then, the seed material and the treating material having a properlyadjusted energy state are contacted with each other at their activatedsurfaces and heated to a temperature capable of causing the grainboundary movement.

This temperature is a temperature required for rearranging the crystalstructure at high energy state to the crystal structure at low energystate, and is generally not lower than recrystallization temperature.

The term "surface of activated state" used herein means an exposedsurface of raw material in the seed material and the treating material,i.e. a surface having no adhesion of impurity or no formation ofimpurity film, or being very small in the presence thereof. Such asurface is obtained by polishing as well as treatment of removingimpurities through so-called cleaning effect with the conventionallywell-known flux such as rosin flux for soldering, inorganic flux ofchloride, fluoride or the like, liquefied cleaning effect with lowmelting point metal, or further various cleaning methods. Particularly,more completed surfaces are obtained by a treatment such as ion etchingunder vacuum or the like. Therefore, the atmosphere for maintaining sucha surface is best to be vacuum state, but the non-oxidizing atmosphereis sufficiently adapted.

Furthermore, in order to completely conduct the joining, the contactingarea is preferable to be made wider as far as possible, and hence thesurface roughness of the contacting surface is favorable to be madesmall as far as possible. Moreover, the reducing of the surfaceroughness is advantageous in view of preventing the remaining ofimpurities in concave portions.

In such a joining, it is preferable to apply stress to the contactingsurface. Because, when the stress is applied, the surface film isdestroyed to develop, for example, a cavitation effect throughapplication of supersonic wave. And also, the dislocation densitylocally increases at the contact interface to provide a more preferableactivated state at high energy state, and even when the flatteningdegree is insufficient, the flattening is promoted through plasticdeformation of concave and convex portions to increase the contact area.As to the component of applied stress, there may be pressure andshearing force with respect to the contacting surface, but thecombination of both forces is more effective. Further, as to theintensity of such a stress, the deformation stress is different inaccordance with the starting material and the heating temperature, sothat the intensity is not particularly restricted, but it is generallyfavorable to apply stress causing no deformation of not less than 30%.

Furthermore, the intensity of the applied stress may be changed with thelapse of time as in the application of a supersonic wave or remainconstant. Particularly, the application of supersonic wave isadvantageous in a point that bubbles in the low melting point substanceinserted into the joint portion are removed to realize the joining ofhigh quality.

There will be described the action of the low melting point substanceinterposed between the seed material and the treating material(hereinafter referred to simply as insert member) below.

The reason why the insert member is interposed between the joint facesis due to the fact that the joining between the seed material and thetreating material is easily realized in a utilizable inert gasatmosphere and the flexibility and easiness of heat diffusion areutilized. The insert member is softened at a relatively low temperaturewith the rising of temperature to increase the closeness of the jointface as a filling member, and further the contracting portion isliquefied above a relatively low melting point or above a eutectictemperature exhibiting the eutectic phenomenon with the matrix to shutoff the joint interface from a harmful atmosphere to thereby prevent thepenetration of impurities into the joint interface. By liquefying thecontacting portion, the breakage of the film and the more closeness canbe expected, and even when the surface treatment is insufficient, thejoining greatly proceeds. Furthermore, the interposition of the insertmember and the rubbing between the joint faces through the applicationof stress are particularly effective for the close joining.

According to the invention, insert members forming a eutectic crystaland/or solid solution with the seed material and the treating materialis advantageously adapted. Because these materials progress thedissolution and diffusion into the matrix through continuous heating toreduce liquid phase and make the joint interface narrower. At this step,as the liquid phase is reduced as far as possible, the joining iscompleted at a joining temperature in a short time.

Thus, the joint face before the heating is favorable to be sufficient inthe closeness and small in the presence of the insert member. Therefore,the roughness of the joint face and the stress applied to the joint facebecome important.

On the other hand, the impurity film on the joint fact such as oxide orthe like is mixed and aggregated with the molten insert member to forman inclusion at the joint interface, and the aggregation is furtherproceeded with the advance of the joining to promote the dissolution,diffusion and scattering into the seed material and the treatingmaterial. As a result, the existence of impurity atom is removed at apart of the joint interface to exhibit the property substantially equalto that of the crystal boundary.

In this way, the distance between atoms in the joint interface isapproached to an extent being substantially equal to the latticeconstant, and consequently the movement of atom becomes possible. Then,the heating is continued at a temperature capable of causing the grainboundary movement, whereby the joint interface disappears and also therearrangement from high energy state to low energy state or the movementof grain boundary occurs to render the whole into a crystal body havingthe predetermined orientation.

The thickness of the insert member is preferred to be thin as far aspossible. Further, as the application method, foil, plating, vapordeposition, spraying, PVD, CVD, ion implantation and the like arepreferable. And also, the insert member is necessary to have a meltingpoint lower than that of the joining material such as seed material,treating material or the like, but the use of eutectic member orsubstance solid soluting in both the materials is more advantageous.Moreover, the proper insert member is different in accordance with thejoining material, and is not particularly restricted. For example, whenthe treating material is iron or iron alloy, the following element or acompound thereof is preferable as the insert member.

Ga, S, In, Se, Sn, Zn, Te, P, Sb, Al, Sr, Ce, As, Ge, Au, Cu, Mn, Be,Si, Bi, Cd, Pb, Ag.

As to the heating, the temperature capable of causing the grain boundarymovement is necessary, and in case of pure metal, it is generallyrequired to have at least recrystallization temperature of this metal.Furthermore, the heating disappears the defect from the joint interfaceto approach to a completely closed ideal joint interface as an atomicsize, so that it is preferable that the temperature is above atemperature lively causing heat diffusion and is higher to an extentthat another orientation grains are not coarsened in the treatingmaterial at high energy state.

As the heating conditions, the uniform temperature heating can usuallybe adapted, but it is more advantageous to give such a temperaturegradient that the temperature drops from low energy substance towardhigh energy substance as utilized in the preparation of single crystalfrom the old time.

As the treating atmosphere, it is important that the harmful oxide filmis not formed on the joint face, and it is particularly preferable thatthe closeness of the joint interface as an atomic size is madesufficient. Therefore, when the insert member is not used, it isfavorable to make vacuum high as far as possible. When the insert memberis used, even if the surface film is somewhat existent as mentionedabove, the film is broken by the liqueficiation of the insert member tomake the surface active, the acceptable range of harmful substancecontained in the atmosphere is loosed to a certain extent as comparedwith the vacuum, but the ratio of the range is different in accordancewith the joining material, insert member, stress, surface state and thelike and is not particularly defined. Furthermore, the atmosphere notreacting with the insert member is favorable until the insert member isdiffused and scattered into the matrix to disappear from the jointinterface, while the harmfulness is determined in accordance with thejoining material after the completion of closeness as the atomic size,so that the atmosphere is not particularly defined. Moreover, when thejoint interface comes into contact with an oxidizing atmosphere, theoxide film is formed to shut off the connecting movement of atomsbetween the seed material and the treating material, so that P₀₂ isparticularly favorable to be lower when the contacting area in the firstembodiment of the invention is small or until the insert member in theseventh embodiment of the invention is liquefied.

SECOND, THIRD, EIGHTH AND NINTH EMBODIMENTS OF THE INVENTION Experiment2-1

A slab or steel comprising C: 0.010%, Si: 3.35%, Mn: 0.15%, S: 0.008%,sol Al: 0.025%, N: 0.0085% and the balance being substantially Fe washeated at 1250° C. for 1 hour and hot rolled to obtain a hot rolledsheet of 0.30 mm in final thickness. Then, four square specimens havinga length: 300 mm and a width: 35 mm were cut out from the thus obtainedhot rolled sheet as raw materials A1, A2, A3 and A4.

Furthermore, the resulting hot rolled sheet was subjected to anannealing at 900° C. for 3 minutes, from which specimens of given shapewere cut out as raw materials AX1, AX2, AX3 and AX4.

Moreover, a hot rolled sheet of 2.3 mm in thickness was formed by hotrolling and immediately cold rolled to obtain a cold rolled sheet of0.30 mm in final thickness, from which specimens of given shape were cutout as raw materials AY1, AY2, AY3 and AY4.

And also, a hot rolled sheet of 2.3 mm in thickness was formed by hotrolling, which was subjected to a normalized annealing at 900° C. for 3minutes and further to two-times cold rolling through an intermediateannealing at 950° C. for 3 minutes to obtain a cold rolled sheet of 0.30mm in final thickness, and thereafter specimens of given shape were cutout therefrom as raw materials AXY1, AXY2, AXY3 and AXY4.

On the other hand, two single crystal plates each comprising Si: 3.0%and the balance being Fe and inevitable impurities and having athickness of 0.30 mm, a length: 280 mm, a width: 5 mm, α=0° and β=2°were provided as raw materials B1 and B2.

Furthermore, two single crystal plates each having the same size asmentioned above, α=0° and β=0° were provided as raw materials C1 and C2.

Then, a section parallel with the rolling direction and perpendicular tothe rolling face in each of A1˜A4, AX1˜AX4, AY1˜AY4, and AXY1˜AXY4, aswell as (110) face perpendicular to plate face in each of B1, B2, C1 andC2 were subjected to Emery polishing, buff polishing and float polishingto render into a mirror state having a center-line average roughness Raof not more than 10 nm, and thereafter a pair of two sets between A, AX,AY or AXY and B and between, A, AX, AY or AXY and C was prepared toobtain (A1, AX1, AY1, AXY1)-B1, (A2, AX2, AY2, AXY2)-B2, (A3, AX3, AY3,AXY3)-C1, (A4, AX4, AY4, AXY4)-C2. After each polished surface of A, AX,AY, AXY, B, C was subjected to an ion sputtering of Ar under high vacuum(10⁻⁶ Torr), the mirrored faces of each of (A1, AX1, AY1, AXY1)-B1 and(A3, AX3, AY3, AXY3)-C1 were contacted with each other so that theprojection axis of [001] axis of B and C was coincident with the rollingdirection of A, AX, AY, AXY, which was annealed at a surface activatedstate under a superhigh vacuum (10⁻¹⁰ Torr), while the mirrored surfacesof each of (A2, AX2, AY2, AXY2)-B2 and (A4, AX4, AY4, AXY4)-C2 after theion sputtering were contacted with each other at a surface inactivestate in a practicable N₂ and then annealed in the practicable N₂, andin this case, the annealing was carried out at 850° C. for 50 hours.Thereafter, they were subjected to a purification annealing at 1180° C.in H₂ for 5 hours.

As a result, crystal grain boundary was formed at the joint face in (A2,AX2, AY2, AXY2)-B2 and (A4, AX4, AY4, AXY4)-C2 to obtain crystal bodiesin which the orientation of A, AX, AY, AXY was different from that ofeach of B, C. On the contrary, no grain boundary was observed at thejoint face in (A1, AX1, AY1, AXY1)-B1 and (A3, AX3, AY3, AXY3)-C1, sothat the resulting joined body was a single crystal body in which theorientation of A1, AX1, AY1, AXY1 was same as in B1 and the orientationof A3, AX3, AY3, AXY3 was same as in C1 when measuring the crystallineorientation around the joint face. That is, the single crystal (nucleusof Goss grain) grew into a matrix without changing the orientation bycontacting and heating while controlling the atmosphere so as not toform the impurity film at the joint face.

Moreover, Table 1-1 shows results measured on magnetic properties ofeach joined body after the application of tension coating.

                  TABLE 1-1                                                       ______________________________________                                                     B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                         ______________________________________                                        A1-B1              2.015   0.92                                               A2-B2              1.72    --                                                 A3-C1              2.021   1.35                                               A4-C2              1.68    --                                                 AX1-B1             2.018   0.91                                               AX2-B2             1.80    --                                                 AX3-C1             2.019   1.42                                               AX4-C2             1.75    --                                                 AY1-B1             2.013   0.89                                               AY2-B2             1.77    --                                                 AY3-C1             2.022   1.45                                               AY4-C2             1.73    --                                                 AXY1-B1            2.015   0.93                                               AXY2-B2            1.76    --                                                 AXY3-C1            2.023   1.37                                               AXY4-C2            1.79    --                                                 ______________________________________                                    

EXPERIMENT 2-2

A slab of steel comprising C: 0.042%, Si: 3.40%, Mn: 0.035%, Se: 0.012%,Sb: 0.020% and the balance being substantially Fe was heated at 1300° C.for 1 hour and hot rolled to obtain a hot rolled sheet of 0.30 mm infinal thickness. Then, four square specimens having a length: 300 mm anda width: 35 mm were cut out from the resulting hot rolled sheet andsubjected to decarburization and primary recrystallization annealing at820° C. in a wet hydrogen for 10 minutes to obtain raw materials A1',A2', A3' and A4'.

The hot rolled sheet was annealed at 900° C. for 3 minutes, from whichthe specimens of given shape were cut out and subjected to the samedecarburization and primary recrystallization annealing as mentionedabove to obtain raw materials AX1', AX2', AX3' and AX4'.

Moreover, a hot rolled sheet of 2.3 mm in thickness as formed by hotrolling and immediately cold rolled to obtain a cold rolled sheet of0.30 mm in final thickness, from which specimens of given shape were cutout and subjected to the same decarburization and primaryrecrystallization annealing to obtain raw materials AY1', AY2', AY3' andAY4'.

And also, a hot rolled sheet of 2.3 mm in thickness was formed by hotrolling, which was subjected to a normalized annealing at 900° C. for 3minutes and further to two-times cold rolling through an intermediateannealing at 950° C. for 3 minutes to obtain a cold rolled sheet of 0.30mm in final thickness, and thereafter specimens of given shape were cutout therefrom and subjected to the same decarburization and primaryrecrystallization annealing to obtain raw materials AXY1', AXY2', AXY3'and AXY4'.

On the other hand, two single crystal plates each comprising Si: 3.0%and the balance being Fe and inevitable impurities and having athickness of 0.30 mm, a length: 280 mm, a width: 5 mm, α=0° and β=2°were provided as raw materials B1 and B2.

Furthermore, two single crystal plates each having the same size asmentioned above α=0° and β=0° were provided as raw materials C1 and C2.

Then, a section parallel with the rolling direction and perpendicular tothe rolling face in each of A1'˜A4', AX1'˜AX4', AY1'˜AY4' andAXY1'˜AXY4' as well as (110) face perpendicular to plate face in each ofB1, B2, C1 and C2 were subjected to Emery polishing, buff polishing andfloat polishing to render into a mirror state having a center-lineaverage roughness Ra of not more than 10 nm, and thereafter a pair oftwo sets between A', AX', AY' or AXY' and B and between A', AX', AY' orAXY' and C was prepared to obtain (A1', AX1', AY1', AXY1')-B1, (A2',AX2', AY2', AXY2')-B2, (A3', AX3', AY3', AXY3')-C1, (A4', AX4', AY4',AXY4')-C2. After each polished surface of A', AX', AY', AXY', B, C wassubjected to an ion sputtering of Ar under high vacuum (10⁻⁶ Torr), themirrored faces of each of (A1', AX1', AY1', AXY1')-B1 and (A3', AX3',AY3', AXY3')-C1 were contacted with each other so that the projectionaxis of [001] axis of B and C was coincident with the rolling directionof A', AX', AY', AXY', which was annealed at a surface activated stateunder a superhigh vacuum (10⁻¹⁰ Torr), while the mirrored surfaces ofeach of (A2', AX2', AY2', AXY2')-B2 and (A4', AX4', AY4', AXY4')-C2after the ion sputtering were contacted with each other at a surfaceinactive state in a practicable N₂ and then annealed in the practicableN₂, and in this case, the annealing was carried out at 850° C. for 50hours. Thereafter, they were subjected to a purification annealing at1180° C. in H₂ for 5 hours.

As a result, crystal grain boundary was formed at the joint face in(A2', AX2', AY2', AXY2')-B2 and (A4', AX4', AY4', AXY4')-C2 to obtaincrystal bodies in which the orientation of A' AX' AY', AXY' wasdifferent from that of each of B, C. On the contrary, no grain boundarywas observed at the joint face in (A1', AX1', AY1', AXY1')-B1 and (A3',AX3', AY3', AXY3')-C1, so that the resulting joined body was a singlecrystal body in which the orientation of (A1', AX1', AY1', AXY1' wassame as in B1 and the orientation of (A3', AX3', AY3', AXY3' was same asin C1 when measuring the crystalline orientation around the joint face.That is, the single crystal (nucleus of Goss grain) grew into a matrixwithout changing the orientation by contacting and heating whilecontrolling the atmosphere so as not to form the impurity film at thejoint face.

Moreover, Table 1-2 shows results measured on magnetic properties ofeach joined body after the application of tension coating.

                  TABLE 1-2                                                       ______________________________________                                                     B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                         ______________________________________                                        A1'-B1             2.011   0.91                                               A2'-B2             1.75    --                                                 A3'-C1             2.018   1.46                                               A4'-C2             1.69    --                                                 AX1'-B1            2.012   0.89                                               AX2'-B2            1.78    --                                                 AX3'-C1            2.021   1.44                                               AX4'-C2            1.71    --                                                 AY1'-B1            2.011   0.92                                               AY2'-B2            1.73    --                                                 AY3'-C1            2.019   1.47                                               AY4'-C2            1.80    --                                                 AXY1'-B1           2.010   0.90                                               AXY2'-B2           1.82    --                                                 AXY3'-C1           2.015   1.45                                               AXY4'-C2           1.75    --                                                 ______________________________________                                    

As seen from Tables 1-1 and 1-2, the magnetic properties even in case ofconducting no annealing and cold rolling (A), or in case of conductingonly annealing (AX) or cold rolling (AY) are approximately equal tothose in case of conducting both the annealing and cold rolling (AXY)irrespectively of the presence or absence of the primaryrecrystallization annealing after the hot rolling.

Even when the single crystal bodies are obtained equally, the iron lossproperties are considerably improved in case of intentionally shifting{110} face of the seed material from the rolling face as compared withthe case of coinciding them.

In order to reduce the cost for advantageously proceeding the industrialproduction, the practicable inert gas (N₂ or Ar) atmosphere isadvantageous rather than vacuum as the atmosphere in the heating. Thispoint is solved by interposing a low melting point metal betweencontacting faces in the joining as mentioned below.

EXPERIMENT 2-3

That is, each of the above raw materials AXY', B and C was subjected toa plate surface treatment of each of

i) pickling with hydrochloric acid;

ii) grinding;

iii) Emery polishing;

iv) chemical polishing;

v) chemical polishing+ion etching

and then the treated surface was subjected to Sn plating at a thicknessof 0.5 μm. Then, Sn plated surfaces were contacted with each other as aset of AXY' and B or AXY' and C and annealed in N₂ atmosphere at 850° C.for 50 hours by varying strain vertically applied to the contactedsurface every the plate surface treating condition and further annealedat 1180° C. in H₂ for 5 hours, and thereafter the presence (x) andabsence (O) of crystal grain boundary at the joint interface wasobserved.

As a result, likewise the case shown in FIG. 2, in the picklingtreatment with hydrochloric acid making the roughness large andretaining many impurities on the surface, the strong applied load wasrequired for disappearing the crystal grain boundary, while in case ofchemical polishing+ion etching making the surface smooth and reducingimpurities, the crystal grain boundary could be disappeared without theapplication of load.

Furthermore, results measured on the magnetic properties at an appliedload of 10 g/mm² are shown in Table 1-3.

                  TABLE 1-3                                                       ______________________________________                                        Treatment for       Applied load 10 g/mm.sup.2                                joint face          B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                ______________________________________                                        AXY'-B  pickling with   1.790   --                                                    hydrochloric acid                                                             grinding        1.810   --                                                    Emery polishing 2.005   0.83                                                  chemical polishing                                                                            2.010   0.80                                                  chemical polishing +                                                                          2.007   0.82                                                  ion etching                                                           AXY'-C  pickling with   1.780   --                                                    hydrochloric acid                                                             grinding        1.790   --                                                    Emery polishing 2.010   1.42                                                  chemical polishing                                                                            2.015   1.35                                                  chemical polishing +                                                                          2.012   1.37                                                  ion etching                                                           ______________________________________                                    

As seen from Table 1-3, even when the insert member is interposed, theimproved iron loss properties were obtained by intentionally shifting{110} face of the seed material from the rolling face.

Although the case of using AXY' as a treating material has mainlydescribed in Experiment 2-3, it has been confirmed that the similarresults are obtained even when the raw materials A, AX, AY, AXY, A',AX', AY' are used as a treating material.

The reason why the crystal grain boundary is disappeared by interposingSn film having a melting point as low as 232° C. is considered to be dueto the same reason described in the above Experiment 1.

From the above experiments, it has been elucidated that grain orientedsilicon steel sheets having the predetermined orientation can easily beproduced by contacting and heating at an activated surface state or inthe presence of the low melting point metal.

Moreover, it has been found that the growth of nucleus planted when theC amount in the starting material is less is particularly good among theexperiments on the low temperature joining technique as mentioned above.

In this connection, the inventors have made further studies and foundout that when conducting the cold rolling, if the C amount in steelbefore the cold rolling is reduced to not more than 0.010%, theoccurrence of nuclei other than the nucleus planted in the lowtemperature joining is effectively suppressed to grow the desiredorientation over the whole of the steel sheet.

EXPERIMENT 2-4

A slab of steel comprising C: 0.080%, Si: 3.30%, Mn: 0.070%, S: 0.020%,sol Al: 0.025%, N: 0.0080% and the balance being Fe and inevitableimpurities was heated at 1340° C. and hot rolled to a thickness of 1.15mm. Then, the hot rolled sheet was subjected to an annealing of

(A) at 1120° C. in N₂ for 2 minutes,

(B) at 1120° C. in N₂ for 2 minutes+at 725° C. in wet hydrogen for 3hours.

In this case, the C amount in the annealed steel sheet was (A) 0.070%and (B) 0.005%. Thereafter, the sheet was cold rolled to a thickness of0.20 mm and subjected to decarburization and primary recrystallizationannealing at 820° C. in a wet hydrogen for 5 minutes, from which a platehaving a length: 300 mm and a width: 500 mm was cut out as a rawmaterial D, E.

Furthermore, a plate having a length: 300 mm and a width: 500 mm was cutout from the cold rolled sheet of the raw material (B) as a raw materialF.

On the other hand, a single crystal plate comprising Si: 3.0% and thebalance being substantially Fe and having a thickness: 0.20 mm, alength: 300 mm, a width: 5 mm, α=0° and β=2.5° was provided as a rawmaterial G.

A section of each of D, E and F parallel with the rolling direction andperpendicular to the rolling face and a face of G perpendicular to theplate face were subjected to Emery polishing to render into a mirrorface of Ra<0.1 μm. After Sn film of 0.5 μm in thickness was formed oneach polished face through plating, the plated face of each of D, E, Fwas closely joined with the plated face of G while applying acompressive load of 10 g/mm² to the joint face, which was fed into atemperature tilting furnace having a temperature gradient of 5° C./cmbetween 1150°˜850° C. at a feed rate of 10 mm/h while holding G at hightemperature side.

Then, MgO as a separator was applied to D, E, F, which was subjected toa purification annealing at 1200° C. in H₂ for 20 hours and thereaftermagnetic properties measured at five positions from G side to obtainresults as shown in the following Table 1-4.

                  TABLE 1-4                                                       ______________________________________                                        Posi- D            E (Invention)                                                                              F (Invention)                                 tion  B.sub.10                                                                              W.sub.17/50                                                                            B.sub.10                                                                            W.sub.17/50                                                                          B.sub.10                                                                            W.sub.17/50                         from G                                                                              (T)     (W/kg)   (T)   (W/kg) (T)   (W/kg)                              ______________________________________                                        1     1.99    0.80     2.00  0.79   1.99  0.80                                2     2.01    0.79     1.99  0.80   1.99  0.80                                3     1.97    0.83     2.01  0.78   2.00  0.80                                4     1.95    0.88     2.00  0.78   2.00  0.79                                5     1.93    0.95     1.99  0.81   2.01  0.78                                ______________________________________                                    

As seen from the above table, in E, F decarburized before the coldrolling, the magnetic properties are not degraded even when it separatesaway from the joint portion with the seed material G. This is due to thefact that there is caused no occurrence of nucleus in another secondaryrecrystallized grains having a shifted orientation during the growingcourse of the seed material G in the decarburized raw materials E, F ascompared with the raw material D. The reason on the occurrence of such aphenomenon is considered to be due to the fact that the formation ofso-called deformation band is suppressed by conducting decarburizationbefore the cold rolling to thereby reduce the nucleus of secondarygrains.

Then, the method of the invention will be described concretely in theorder of the production steps.

As the starting material according to the invention, anyone of rawmaterials comprising C: not more than 1.0%, Si: 0.1˜7.0% and Mn:0.002˜1.5% as a main component and containing at least one of P:0.010˜0.050%, S: 0.005˜0.05%, Se: 0.005˜0.05%, Te: 0.003˜0.03%, Sb:0.005˜0.100%, Sn: 0.03˜0.5%. Cu: 0.02˜0.3%, Mo: 0.005˜0.05%, B:0.0003˜0.0040%, N: 0.001˜0.02%, Al: 0.005˜0.10%, Ti: 0.001˜0.05%, V:0.001˜0.05%, Cr: 0.05˜0.5% and Nb: 0.001˜0.05% as an inhibitor formingcomponent are advantageously adaptable.

These raw materials are made by the conventionally well-knownsteel-making methods such as steel-making in convertor or electricfurnace and further shaped into a slab or a sheet bar through ingotblooming method, continuous casting method or roll rapid quenchingmethod or the like, or into this steel sheet directly.

In general, the heating is carried out at a temperature of not lowerthan 1350° C. for completely soluting the inhibitor component into theslab. In the invention, it is not particularly necessary to conduct theslab heating treatment at a high temperature above 1350° C. as mentionedabove, and it is enough to conduct low-temperature slab heatingtreatment below about 1250° C. as in the ordinary steel. Because, thecrystalline orientation of the steel sheet is fully dependent upon theseed material in the invention, so that it is sufficient to strictlycontrol only the orientation of the seed material into a desirableorientation and it is not necessary to make the inhibitor strong as faras possible for aligning the orientation of the nucleus. Further, theorientation of the steel sheet as a treating material is not necessaryto be strictly controlled, and hence it is not required to completelysolute the inhibitor component into steel at the slab heating stage.

In the invention, therefore, not only the energy-saving is attained, butalso there is caused no abnormal coarsening of crystal structure, whichhas been apprehended in the high-temperature slab heating, so that theuniform and fine crystal structure is obtained through thelow-temperature slab heating.

Thereafter, silicon-containing steel sheets are obtained by hot rolling.Then, the sheet is treated without annealing and cold rolling, orsubjected to an annealing (normalized annealing or intermediateannealing) and/or cold rolling at least one time. Immediately thereafteror after primary recrystallization annealing, the sheet is subjected toa finish annealing. In this case, the normalized annealing orintermediate annealing aims at the recrystallization treatment anddecarburization treatment for homogenizing the crystal structure afterthe rolling, and is usually carried out at 700°˜1200° C. for 30seconds˜10 minutes. In the invention, it is preferable that even in caseof conducting the cold rolling, when the C amount in the startingmaterial exceeds 0.01%, such a normalized annealing or intermediateannealing is a decarburization annealing adjusting an oxygen potentialin the atmosphere or the annealing time and the C amount in steel beforethe final cold rolling is reduced to not more than 0.010%. Because, byreducing the C amount in steel before the final cold rolling to not morethan 0.010%, the planted secondary recrystallized nucleus is stablygrown over the whole of the steel sheet as previously mentioned.

The reason why the C amount is steel before the final cold rolling islimited to not more than 0.010% is due to the fact that when the Camount exceeds the above value, the formation of so-called deformationband becomes active and the occurrence frequency of α, β shifted nucleiin the primary grains forming the secondary grains increases to easilygenerate and grow largely α, β shifted secondary grains.

Then, a primary recrystallization annealing is carried out, ifnecessary. As the primary recrystallization annealing, the slow heatingat a rate of, for example, about 20° C./h over a long time forcompleting the primary recrystallization (˜700° C.) or a treatment ofmaintaining a temperature at 550° C. for about 24 hours is advantageousfor not only the fine homogenization and stabilization of inhibitor butalso the decrease of (110) component and increase of (111) component.Thereafter, the annealing is carried out under atmosphere of oxygenpotential, temperature and time in accordance with the C amount, forexample, in a set hydrogen at 700°˜900° C. for about 1˜15 minutes,whereby C in steel is removed and also primary recrystallization texturesuitable for developing secondary recrystallized grains of Gossorientation in the subsequent annealing is formed.

Thereafter, the sheet is subjected to secondary recrystallizationannealing at 800°-1100° C. for about 1˜50 hours and further topurification annealing at 1100°-1250° C. for about 5˜25 hours. Accordingto the invention, at a step after the hot rolling and before the finishannealing in both cases, a seed material having an orientation is joinedto an edge portion of the steel sheet so as to control the orientationof the seed material into

    |α|≦5°

    1≦|β|≦5°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of <001> axis of seed material with respect torolling face of steel sheet.

The reason why the orientations of the seed material and the steel sheetare limited to |α|≦5° and |β|=1°˜5° is as follows.

At first, as regards α, when |α| exceeds 5°, the degradation of B₁₀value becomes excessive and the expected improvement of magneticproperties can not be obtained.

Secondly, as regards β, when |β|<1°, the width of magnetic domainbecomes excessively large to bring about the degradation of the ironloss, while when |β|>5°, the B₁₀ value is degraded and hence the ironloss is also degraded.

In the above joining, it is important to contact the joint faces at anactivated state of to interpose an insert member having a low meltingpoint between the joint faces.

The reason on the above is same as described in the above Experiment 1.

After the seed material and the treating material are contacted witheach other at the activated state or joined through interposition of theinsert member, they are heated to a temperature causing grain boundarymovement.

The term "temperature causing grain boundary movement" used herein meansa temperature required for rearranging the crystal structure to changeinto a new crystal structure and generally is not lower than therecrystallization temperature.

In such a heat treatment, it is important that the steel sheet as thetreating material is at an energy state higher than that of the seedmaterial. Because, the seed material can not grow when the energy stateof the seed material is equal to or higher than that of the steel sheet.

The term "energy state" used herein is concerned with inner strain andsurface as previously mentioned, and is mainly dependent upon quantitiesand masses of crystal grain boundary, dislocation, point defect andsurface energy of crystal. As these quantities increase, the higher theenergy state. Moreover, the seed materials used in the second, third,eighth and ninth embodiments of the invention are mainly single crystalshaving an aligned orientation, while the steel sheets as the treatingmaterial are not only polycrystalline bodies but also contain arelatively large amount of dislocation or the like. Therefore, theenergy state in the steel sheet is generally higher than that of theseed material, so that it is not usually required to take a specialtreatment for adjustment of energy state. According to circumstances,for example, when the primary grain size is excessively large, it isadvantageous to conduct a treatment for the introduction of strain orthe like. Furthermore, in order to hold the high energy state constantin the annealing, it is necessary to control the primary grain sizeconstant. For this purpose, it is effective to add at least one of N, S,Se, Te and compounds thereof to the separator in addition to theinhibitor originally contained in the steel sheet.

The adequate temperature is different in accordance with the matrix andthe production step, i.e., the energy state of the treating material orthe like, but it is usually 650°˜1200° C., preferably 800°˜1150° C.

Furthermore, the heating system and the treating atmosphere are the sameas described in Experiment 1.

Moreover, in the invention, when the joining treatment of the seedmaterial is particularly just before the finish annealing, thesubsequent heating treatment may be the finish annealing.

And also, when the raw material containing a relatively large amount ofC is used and the decarburization treatment is not carried out up to thefinish annealing, it is favorable that the annealing atmosphere isadjusted to a decarburization property by using MgO containing saturatedcrystal water or the like as a main component of an annealing separatorin the subsequent secondary recrystallization annealing, whereby thedecarburization is carried out before the growth of secondary grains.

In addition, according to the invention, the magnetic properties can bemore improved by applying a tension-type thin coating to the surface ofthe steel sheet after the purification annealing in the well-knownmanner, or by introducing strain into the steel sheet to refine magneticdomains.

FOURTH, FIFTH, TENTH AND ELEVENTH EMBODIMENTS OF THE INVENTIONExperiment 3-1

A slab of steel comprising C: 0.042%, Si: 3.40%, Mn: 0.035%, Se: 0.012%,Sb: 0.020%, Al: 0.025%, N: 0.0085% and the balance being substantiallyFe was heated at 1300° C. for 1 hour, hot rolled to a thickness of 2.3mm, and then subjected to a cold rolling two times, wherein a first coldrolling was made in parallel to the hot rolling direction at a reductionof 70% and a second cold rolling was made in a direction perpendicularthereto at a reduction of 57%, to obtain a cold rolled sheet having afinal thickness of 0.30 mm. From the thus obtained cold rolled sheetwere cut out four plates having a length: 300 mm and a width: 35 mm asraw materials A1, A2, whose longitudinal direction being the same as inthe first rolling direction, and raw materials A3, A4, whoselongitudinal direction being the same as in the second rollingdirection.

On the other hand, four single crystal plates having the same chemicalcomposition as in the above cold rolled sheet and a thickness: 0.30 mm,a length: 280 mm, a width: 5 mm and a plate face of (100) were providedas raw materials B1, B2, B3, B4.

Then, a section parallel with the longitudinal direction andperpendicular to the rolling face in each of A1˜A4 as well as (110) faceperpendicular to plate face in each of B1, B2, B3, B4 were subjected toEmery polishing, buff polishing and float polishing to render into amirror state having a center-line average roughness Ra of not more than10 nm, and thereafter four sets of a pair of A and B were prepared toobtain A1-B1, A2-B2, A3-B3, A4-B4. After each polished surface of A, Bwas subjected to an ion sputtering of Ar under high vacuum (10⁻⁶ Torr),the mirrored faces of each of A1-B1 and A3-B3 were contacted with eachother so that [001] axis of B was coincident with the rolling directionof A, which was heated at a surface activated state under a superhighvacuum (10⁻¹⁰ Torr), while the mirrored surfaces of each of A2-B2 andA4-B4 after the ion sputtering were contacted with each other at asurface inactive state in a practicable N₂ and then heated in thepracticable N₂, and in both cases, the heating was carried out from 200°C. at a temperature rising rate of 20° C./h and subjected to anannealing at 970° C. for 50 hours. Thereafter, they were subjected to apurification annealing at 1180° C. in H₂ for 5 hours.

As a result, crystal grain boundary was formed at the joint face inA2-B2 and A4-B4 to obtain crystal bodies in which the orientationsbetween A2 and B2 and between A4 and B4 was different from each other.On the contrary, no grain boundary was observed at the joint face inA1-B1 and A3-B3, so that the resulting joined body was a single crystalbody in which the orientation of A1, A3 was same as in B1 and B3 whenmeasuring the crystalline orientation around the joint face. That is,the single crystal (nucleus of Goss grain) grew into a matrix withoutchanging the orientation by contacting and heating while controlling theatmosphere so as not to form the impurity film at the joint face.

Moreover, Table 2-1 shows results measured on magnetic properties ofeach joined body in the longitudinal direction.

                  TABLE 2-1                                                       ______________________________________                                        B.sub.10 (T)    W.sub.17/50 (W/kg)                                                                        Remarks                                           ______________________________________                                        A1-B1   2.018       1.43        invention                                     A2-B2   1.38        --          --                                            A3-B3   2.019       1.45        invention                                     A4-B4   1.41        --          --                                            ______________________________________                                    

EXPERIMENT 3-2

Four square plates cut out in the same manner as in Experiment 3-1 wereheated from 200° C. to 700° C. at a temperature rising rate of 20° C./hand then subjected to decarburization and primary recrystallizationannealing at 820° C. in a wet hydrogen for 3 minutes in which rawmaterials having a longitudinal direction same as in the first rollingdirection were A1' and A2' and raw materials having a longitudinaldirection same as in the second rolling direction were A3', A4'.

On the other hand, four single crystal plates having the same chemicalcomposition as in the above cold rolled sheet and a thickness: 0.30 mm,a length: 280 mm, a width: 5 mm and a plate face of (100) were providedas raw materials B1', B2', B3', B4'.

Then, a section parallel with the longitudinal direction andperpendicular to the rolling face in each of A1'˜A4' as well as (100)face perpendicular to plate face in each of B1', B2', B3', B4' weresubjected to Emery polishing, buff polishing and float polishing torender into a mirror state having a center-line average roughness Ra ofnot more than 10 nm, and thereafter four sets of a pair of A' and B'were prepared to obtain A1'-B1', A2'-B2', A3'-B3', A4'-B4'. After eachpolished surface of A', B' was subjected to an ion sputtering of Arunder high vacuum (10⁻⁶ Torr), the mirrored faces of each of A1'-B1' andA3'-B3' were contacted with each other so that [001] axis of B' wascoincident with the rolling direction of A', which was annealed at asurface activated state under a superhigh vacuum ( 10⁻¹⁰ Torr), whilethe mirrored surfaces of each of A2'-B2' and A4'-B4' after the ionsputtering were contacted with each other at a surface inactive state ina practicable N₂ and annealed in the practicable N₂, and in this casethe annealing was carried out at 970° C. for 50 hours. Thereafter, theywere subjected to a purification annealing at 1180° C. in H₂ for 5hours.

As a result, crystal grain boundary was formed at the joint face inA2'-B2' and A4'-B4' likewise Experiment 3-1 to obtain crystal bodies inwhich the orientations between A2' and B2' and between A4' and B4' wasdifferent from each other. On the contrary, no grain boundary wasobserved at the joint face in A1'-B1' and A3'-B3', so that the resultingjoined body was a single crystal body in which the orientation of A1',A3' was same in B1' and B3' when measuring the crystalline orientationaround the joint face.

Moreover, Table 2-2 shows results measured on magnetic properties ofeach joined body in the longitudinal direction.

                  TABLE 2-2                                                       ______________________________________                                               B.sub.10 (T)                                                                            W.sub.17/50 (W/kg)                                                                        Remarks                                          ______________________________________                                        A1'-B1'  2.015       1.42        invention                                    A2'-B2'  1.35        --          --                                           A3'-B3'  2.020       1.41        invention                                    A4'-B4'  1.30        --          --                                           ______________________________________                                    

EXPERIMENT 3-3

A steel slab having the same chemical composition as in Experiment 3-1was hot rolled to a thickness of 2.3 mm in the same manner, subjected toa normalized annealing at 1020° C. for 3 minutes and cold rolled in thesame manner as in Experiment 3-1, from which four square plates having alength: 300 mm and a width: 35 mm were cut out as raw materials A1", A2"having a longitudinal direction same as in the first rolling directionand raw materials A3", A4" having a longitudinal direction same as inthe second rolling direction. Thereafter, they were subjected todecarburization and primary recrystallization annealing at 820° C. for 3minutes.

On the other hand, four single crystal plates having the same chemicalcomposition as in the above cold rolled sheet and a thickness: 0.30 mm,a length: 280 mm, a width; 5 mm and a plate face of (100) were providedas raw materials B1", B2", B3", B4".

Then, a section parallel with the longitudinal direction andperpendicular to the rolling face in each of A1"˜A4" as well as (100)face perpendicular to plate face in each of B1", B2", B3", B4" weresubjected to Emery polishing, buff polishing and float polishing torender in to a mirror state having a center-line average roughness Ra ofnot more than 10 nm, and thereafter four sets of a pair of A" and B"were prepared to obtain A1"-B1", A2"-B2", A3"-B3", A4"-B4". After eachpolished surface of A", B" was subjected to an ion sputtering of Arunder high vacuum (10⁻⁶ Torr), the mirrored faces of each of A1"-B1" andA3"-B3" were contacted with each other so that [001] axis of B" wascoincident with the rolling direction of A", which was annealed at asurface activated state under a superhigh vacuum (10⁻¹⁰ Torr), while themirrored surfaces of each of A2"-B2" and A4"-B4" after the ionsputtering were contacted with each other at a surface inactive state ina practicable N₂ and annealed in the practicable N₂, and in both casesthe annealing was carried out at 970° C. for 50 hours. Thereafter, theywere subjected to a purification annealing at 1180° C. in H₂ for 5hours.

As a result, crystal grain boundary was formed at the joint face inA2"-B2" and A4"-B4" likewise Experiment 3-1 to obtain crystal bodies inwhich the orientations between A2" and B2" and between A4" and B4" wasdifferent from each other. On the contrary, no grain boundary wasobserved at the joint face in A1"-B1" and A3"-B3", so that the resultingjoined body was a single crystal body in which the orientation of A1",A3" was same in B1" and B3" when measuring the crystalline orientationaround the joint face.

Moreover, Table 2-3 shows results measured on magnetic properties ofeach joined body in the longitudinal direction.

                  TABLE 2-3                                                       ______________________________________                                               B.sub.10 (T)                                                                            W.sub.17/50 (W/kg)                                                                        Remarks                                          ______________________________________                                        A1"-B1"  2.005       1.40        invention                                    A2"-B2"  1.83        --          --                                           A3"-B3"  2.010       1.38        Invention                                    A4"-B4"  1.57        --          --                                           ______________________________________                                    

Thus, according to the fourth and fifth inventions, very good magneticproperties were obtained in any directions crossing on the rolling face.Particularly, when the primary recrystallization after the cold rollingis the gradual heating and annealing, the strong effect of suppressingthe grain growth is obtained through the reduction of (110) component ofthe treating material and the uniform fine division and stabilization ofinhibitor to facilitate the growth of the seed material and henceprovide excellent magnetic properties.

Moreover, in order to advantageously proceed the industrial productionby more reducing the cost, the atmosphere in the heating is favorable tobe practicable inert gas (N₂ or Ar) atmosphere rather vacuum asdescribed on the above production method of grain oriented silicon steelsheets. This point was solved by joining through the interposition oflow melting point substance between joint faces as mentioned above.

EXPERIMENT 3-4

That is, each of the above raw materials A1, A3 and B1, B3 was subjectedto a plate surface treatment of each of

i) pickling with hydrochloric acid;

ii) grinding;

iii) Emery polishing;

iv) chemical polishing;

v) chemical polishing+ion etching

and then the treated surface was subjected to Sn plating at a thicknessof 0.5 μm. Then, Sn plated surfaces were contacted with each other as aset of A1 and B1 or A3 and B3 and heated in N₂ atmosphere from 200° C.at a temperature rising rate of 20° C./h by varying strain verticallyapplied to the contacted surface every the plate surface treatingcondition and further annealed at 970° C. for 50 hours and at 1180° C.in H₂ for 5 hours, and thereafter the presence (x) and absence (O) ofcrystal grain boundary at the joint interface was observed.

As a result, likewise the case shown in FIG. 2, in the picklingtreatment with hydrochloric acid making the roughness large andretaining many impurities on the surface, the strong applied load wasrequired for disappearing the crystal grain boundary, while in case ofchemical polishing+ion etching making the surface smooth and reducingimpurities, the crystal grain boundary could be disappeared without theapplication of load.

Furthermore, results measured on the magnetic properties at an appliedload of 10 g/mm² are shown in Table 2-4.

                  TABLE 2-4                                                       ______________________________________                                                        Applied load 10 g/mm.sup.2                                    Treatment for              W.sub.17/50                                        joint face        B.sub.10 (T)                                                                           (W/kg)   Remarks                                   ______________________________________                                        A1-B1  pickling with  1.350    --                                                    hydrochloric acid                                                             grinding       1.790    --                                                    Emery polishing                                                                              2.017    1.46                                                  chemical polishing                                                                           2.021    1.47   Inven-                                                                        tion                                           chemical polishing +                                                                         2.042    1.49                                                  ion etching                                                            A3-B3  pickling with  1.450    --                                                    hydrochloric acid                                                             grinding       1.750    --                                                    Emery polishing                                                                              2.015    1.42                                                  chemical polishing                                                                           2.022    1.45   Inven-                                                                        tion                                           chemical polishing +                                                                         2.031    1.48                                                  ion etching                                                            ______________________________________                                    

EXPERIMENT 3-5

Furthermore, each of the raw materials A1', A3' and B1', B3' as well asA1", A3" and B1", B3" subjected to the decarburization and primaryrecrystallization annealing before the finish annealing was subjected tothe plate surface treatment and the plating treatment in the same manneras in Experiment 2-1 and then the plated surfaces were contacted witheach other as a set of A1', and B1', A3' and B3', A1" and B1" or A3" andB3" and annealed in N₂ atmosphere at 970° C. for 50 hours and further at1180° C. in H₂ for 5 hours, and thereafter the presence (x) and absence(O) of crystal grain boundary at the joint interface was observed. As aresult, there were obtained results approximately similar to the caseshown in FIG. 2. Furthermore, results measured on the magneticproperties at an applied load of 10 g/mm² are shown in Table 2-5.

                  TABLE 2-5                                                       ______________________________________                                                        Applied load 10 g/mm.sup.2                                    Treatment for              W.sub.17/50                                        joint face        B.sub.10 (T)                                                                           (W/kg)   Remarks                                   ______________________________________                                        A1'-B1'                                                                              pickling with  1.530    --                                                    hydrochloric acid                                                             grinding       1.820    --                                                    Emery polishing                                                                              2.015    1.47                                                  chemical polishing                                                                           2.010    1.43   Inven-                                                                        tion                                           chemical polishing +                                                                         2.035    1.45                                                  ion etching                                                            A3'-B3'                                                                              pickling with  1.620    --                                                    hydrochloric acid                                                             grinding       1.801    --                                                    Emery polishing                                                                              2.010    1.45                                                  chemical polishing                                                                           2.020    1.39   Inven-                                                                        tion                                           chemical polishing +                                                                         2.045    1.47                                                  ion etching                                                            A1"-B1"                                                                              pickling with  1.780    --                                                    hydrochloric acid                                                             grinding       1.815    --                                                    Emery polishing                                                                              2.010    1.45                                                  chemical polishing                                                                           2.005    1.42   Inven-                                                                        tion                                           chemical polishing +                                                                         2.010    1.43                                                  ion etching                                                            A3"-B3"                                                                              pickling with  1.790    --                                                    hydrochloric acid                                                             grinding       1.795    --                                                    Emery polishing                                                                              2.005    1.43                                                  chemical polishing                                                                           2.015    1.37   Inven-                                                                        tion                                           chemical polishing +                                                                         2.010    1.39                                                   ion etching                                                           ______________________________________                                    

Thus, according to the tenth and eleventh embodiments of the invention,very good magnetic properties were obtained in any directions crossingon the rolling face even in the practicable atmosphere.

The reason why the crystal grain boundary is disappeared by interposingthe Sn film having a melting point as low as 232° C. is considered to bethe same as described in Experiment 1.

From the above experimental results, it has been found out that thebidirectional oriented silicon steel sheets can easily be produced byheating with the holding of the activated state or under theinterposition of the low melting point metal.

Then, these invention methods will concretely be described in the orderof production steps.

At first, the starting material according to the invention issubstantially the same as in the grain oriented silicon steel sheet, andanyone or raw materials comprising C: 0.005˜1.0%, Si: 0.1˜7.0% and Mn:0.002˜1.5% as a main component and containing at least one of S:0.005˜0.05%, Se: 0.005˜0.05%, Te: 0.003˜0.03%, Sb: 0.005˜0.100%, Sn:0.03˜0.5%, Cu: 0.02˜0.3%, Mo: 0.005˜0.05%, B: 0.0003˜0.0040%, N:0.001˜0.02%, Al: 0.005˜0.10%, Ti: 0.001˜0.05%, V: 0.001˜0.05% and Nb:0.001˜0.05% as an inhibitor forming component are advantageouslyadaptable.

These raw materials are made by the conventionally well-knownsteel-making methods such as steel-making in convertor or electricfurnace and further shaped into a slab or a sheet bar through ingotblooming method, continuous casting method or roll rapid quenchingmethod or the like, or into this steel sheet directly and thereafter hotrolling, warm or cold rolling is carried out to form asilicon-containing steel sheet, if necessary. Then, the desiredthickness is provided by a normalized annealing or further one or morecold rolling including an intermediate annealing, if necessary. As tothe cold rolling, it is effective to conduct the cold rolling bycrossing the rolling direction as disclosed in Japanese PatentApplication Publication No. 35-2657.

That is, it is easy and economical in industry that the first coldrolling is carried out in the same direction as in the hot rollingdirection and then cut into a constant length and subjected to thesecond cold rolling in a direction perpendicular thereto at a sheetstate, or after the cutting into a constant length, the sheets arewelded to form a strip, which is continuously subjected to the coldrolling. Moreover, the normalized annealing or intermediate annealingaims at the recrystallization treatment and decarburization treatmentfor homogenizing the crystal structure after the rolling, and is usuallycarried out at 700°˜1200° C. for 30 seconds˜10 minutes. In theinventions, it is preferable that even in case of conducting the coldrolling, when the C amount in the starting material exceeds 0.01%, sucha normalized annealing or intermediate annealing is a decarburizationannealing adjusting an oxygen potential in the atmosphere or theannealing time and the C amount in steel before the final cold rollingis reduced to not more than 0.010%. The reason is the same as describedin the production of the grain oriented silicon steel sheet.

Then, a primary recrystallization annealing is carried out, ifnecessary. As the primary recrystallization annealing, the slow heatingat a rate of, for example, about 20° C./h over a long time forcompleting the primary recrystallization (˜700° C.) or a treatment ofmaintaining a temperature at 550° C. for about 24 hours is advantageousfor not only the fine homogenization and stabilization of inhibitor butalso the decrease of (110) component and increase of (111) component.Such an annealing is carried out under atmosphere of oxygen potential,temperature and time in accordance with the C amount, for example, in awet hydrogen at 700°˜900° C. for about 1˜15 minutes, whereby C in steelis removed and also primary recrystallization texture suitable fordeveloping secondary recrystallized grains of Goss orientation in thesubsequent annealing is formed.

Thereafter, the sheet is subjected to secondary recrystallizationannealing at 800°˜1100° C. for about 1˜50 hours and further topurification annealing at 1100°˜1250° C. for about 5˜25 hours. Accordingto the invention, a seed material having an orientation is joined to anedge portion of the steel sheet so as to control the orientation of theseed material into

    |α|≦10°

    |β|≦10°

where

α: angle defined by a projection line of <001> axis of seed materialwith respect to rolling face of steel sheet and the rolling direction ofsteel sheet;

β: inclination angle of {100} face of seed material with respect torolling face of steel sheet

at a stage after the hot rolling and before the purification annealing.

The reason why α and β are limited to |α|, |β|≦10° is due to the factthat when |α|, |β| exceed 10°, the degradation of B₁₀ value becomesexcessive and the given magnetic properties are not obtained.

In the above joining, it is important to contact the joint faces at anactivated state or to interpose an insert member having a low meltingpoint between the joint faces.

The reason on the above is the same as described in the above Experiment1.

After the seed material and the treating material are contacted witheach other at the activated state or joined through interposition of theinsert member, they are heated to a temperature causing grain boundarymovement likewise the aforementioned case of producing the grainoriented silicon steel sheet.

Moreover, the heating conditions and the heating atmosphere may be thesame as in the production of the grain oriented silicon steel sheet.

In addition, according to these inventions, the magnetic properties canbe more improved by applying a tension-type thin coating to the surfaceof the steel sheet after the purification annealing in the well-knownmanner, or by introducing strain into the steel sheet to refine magneticdomains.

SIXTH AND TWELFTH EMBODIMENTS OF THE INVENTION Experiment 4

As mentioned in Experiments 1˜3, it has been elucidated that substanceshaving a given orientation can easily be produced by heating withholding the activated state or under the interposition of the lowmelting point metal. In order to promote the mass production inindustrial scale, however, it is advantageous to realize the heating ata coiled state of the steel sheet.

The sixth and twelfth inventions described herein advantageously realizethe heating treatment at such a coiled state.

As the method of planting a seed material onto the coiled steel sheet, amost ideal method is the coincidence of curvature of the steel sheetwith curvature of the seed material in the joining. That is, aplate-like seed material of a given shape is joined to the rolling faceof the steel sheet and coiled, or a coiled steel sheet and a coiled seedmaterial having the same curvature as in the sheet are piled one uponthe other and then joined. However, the joining of the seed material tothe elongated steel sheet over the full length thereof prior to thecoiling is necessary to take a complicated and long time treating step,and also the joining between the edges of the coils has a problem thatthe control of orientation is difficult.

However, this problem can be solved by radially arranging an orientationcontrolled strip-like seed material onto an edge portion of the coil andjoining them as shown in FIG. 3a. In FIG. 3a, a distance between theseed materials to be planted in the circumferential direction is l, andan angle corresponding to l when the seed material grows to l is β.Here, β shows a shifting of the seed material from the rolling face ofthe steel sheet having an orientation in a tangential direction of thecoil when the seed material or crystal grain grown from the seedmaterial displaces by l in the circumferential direction. That is, theorientation of the seed material shifts by β from the rolling face ofthe steel sheet when the seed material grows by l.

Since the curvature is existent in the steel sheet at such a coiledstate, even if the orientation of the strip-like seed material isstrictly controlled, the shifting of the orientation from the rollingface of the steel sheet is unavoidable at the stage of the crystalgrowth. In this point, the shifting can be mitigated to an extent thatthere is actually caused no problem by shortening the planting distanceof the seed material in the circumferential direction.

In FIG. 4 is shown a relationship between l and β in outermost coil andinnermost coil when an outer diameter is 1000 mm and an inner diameteris 550 mm. The shorter the planting distance of the seed material or thelarger the coil diameter or the smaller the curvature, the smaller theshifting (β) of orientation of the coiled body from the seed material.However, the enlargement of the coil diameter is critical, so that it isfavorable to shorten the planting distance of the seed material forsuppressing the shifting of the orientation.

In case of a coil having an inner diameter of 550 mm, assuming that onecrystal grows from one seed material, in order to control an averageshifting angle β_(av) of β in the longitudinal direction of the steelsheet to not more than 10°, it is necessary that the crystal length ofthe inner coil portion in the circumferential direction is restrained tonot more than 100 mm being about 2 times of the crystal length at β=10°judging from FIG. 4. Similarly, it should be restrained to not more than180 mm in the outer coil portion having a diameter 1000 mm. Therefore,the planting distance of the seed material is necessary to be 100 mm inorder to obtain β_(av) ≦10° over the full length of the coil.

As the planting method for the seed material, it is not necessary tocontinuously extend the seed material in the radial direction, and thediscontinuous state may be taken as shown in FIG. 3b. Furthermore, asshown in FIG. 3c, it is not necessarily required to radially arrange theseed material, and in this case it is necessary to change theorientation of the seed material in accordance with the arrangingposition of the seed material for holding the given orientation relationto the coil.

Then, the invention method will be described concretely in the order ofthe production steps.

Firstly, all substances described in the first˜fifth embodiments of theinvention and seventh˜eleventh embodiments of the invention areadaptable as the treating material and the seed material.

Moreover, the shape of the seed material may be coil-like as previouslymentioned, but is preferable to radially arrange on a helical edge faceof the coil as a strip.

And also, the helical edge face of the coil is favorable to be subjectedto a smoothening treatment for removing surface unevenness or strainintroduced portion. Moreover, in order to prevent the shifting betweenthe coil-like steel sheets after the smoothening treatment, it isadvantageous that edge faces of the steel sheets opposite to the givensmoothening faces are joined through welding to mutually fix these steelsheets to each other prior to the smoothening treatment.

After the seed material and the treating material are contacted witheach other at the activated state or joined through interposition of theinsert member, they are heated to a temperature causing grain boundarymovement.

Moreover, the heating conditions and the heating atmosphere may be thesame as previously mentioned in accordance with the properties of theseed material and the treating material.

BRIEF EXPLANATION OF DRAWING

FIGS. 1a, b, c and d are flow sheets showing the production of crystalbody having a particular orientation according to the conventionalmethod, respectively;

FIG. 2 is a graph showing influences of surface polished state of ajoined body and an applied load upon disappearance of crystal grainboundary at joint face;

FIGS. 3, 3a, b and c are schematic views showing a placing state of aseed material onto a helical edge face of a coil according to theinvention, respectively; and

FIG. 4 is a graph showing a relationship between planting distance ofseed material and shifting of orientation from rolling face using a coildiameter as a parameter.

BEST MODE OF CARRYING OUT THE INVENTION Example 1

A block of Ag having a purity of 99.99% was divided into two parts A, B.The part A was annealed at 800° C. under vacuum (10⁻⁶ Torr) for 24 hoursto make recrystallized grains course. From these coarse grains were cutout single crystal plates of 1 mm thickness and 10 mm□ by electric arcmethod so as to render the orientation of plate face into (100), (110),(111) as seed plates C, D, E.

On the other hand, the part B was rolled to obtain a sheet of 1 mm inthickness, which was annealed at 300° C. under vacuum (10⁻⁶ Torr) for 30minutes and 3% strain was introduced thereinto under tension to renderinto a high energy state as compared with the seed plates, and thenthree sheets 10 mm□ were cut out therefrom as treating sheets B₁, B₂,B₃.

Then, the plate faces of B₁, B₂, B₃, C, D, E were finished into a mirrorstate of Ra≦0.01 μm by Emery polishing, buff polishing or floatpolishing. After the polished face was activated by argon ionbombardment under vacuum (10⁻¹⁰ Torr), the polished face of each of C,D, E was contacted edgewise with and joined to the polished face of eachof B₁, B₂, B₃ under vacuum, which was heated at 350° C. for 100 hours.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the sectional structureat the joint interface, and also each of the joined B₁, B₂, B₃ wasconfirmed to be a crystal body having the same orientation as in each ofC, D, E from the measured results of crystalline orientation.

Example 2

From a block-like coarse grain comprising 3% of Si and the balance beingFe and inevitable impurities were cut out three single crystal plates of0.5 mm thickness and 10 mm□ by electric arc method so as to render theplate face into (100), (110), (111) as seed plates B, C, D.

On the other hand, a steel ingot comprising C: 0.002%, Mn: 0.001%, S:0.002%, P: 0.001%, O: 0.001% and the balance being Fe and inevitableimpurities was hot rolled to obtain a hot rolled sheet of 2 mm inthickness, which was cold rolled in a direction perpendicular to the hotrolling direction to obtain a cold rolled sheet of 0.5 mm in thickness.This sheet was annealed at 820° C. in dry Ar for 10 minutes and 3%strain was introduced thereinto under tension to render into a highenergy state as compared with the seed plates, from which three sheetsof 10 mm□ were cut out as treating sheets A₁, A₂, A₃.

Then, each plate face of A₁, A₂, A₃, B, C, D was finished into a mirrorsurface of Ra≦0.2 μm by Emery polishing. After Sn film of 1 μm inthickness was plated onto the polished face, the plated face of each ofB, C, D was closely joined to the plated face of each of A₁, A₂, A₃,which was heated at 850° C. in dry Ar atmosphere for 24 hours whileapplying a compressive stress of 10 g/mm² to the joint face.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the sectional structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 3

From a block-like coarse grain comprising 3% of Si and the balance beingFe and inevitable impurities were cut out three single crystal plates of1 mm thickness and 10 mm□ by electric arc method so as to render theplate face into (100), (110), (111) as seed plates B, C, D.

On the other hand, a steel ingot comprising Al: 2.5% and the balancebeing Fe and inevitable impurities was hot rolled to obtain a hot rolledsheet of 1 mm in thickness, which was annealed at 900° C. in dry Ar for30 minutes and 2.5% tensile strain was introduced thereinto to renderinto a high energy state as compared with the seed material, from whichthree sheets of 10 mm□ were cut out as treating sheets A₁, A₂, A₃.

Then, each thickness face as section perpendicular to plate face of A₁,A₂, A₃ in the rolling direction, B, C in [001] orientation, D in [112]orientation was finished into a mirror surface of Ra≦0.2 μm by Emerypolishing. After Sn film of 1.5 μm in thickness was plates onto thepolished face, the plated face of each of B, C, D was closely joined tothe plates face of each of A₁, A₂, A₃, which was heated by feeding intoa temperature tilting furnace having a temperature gradient of 125°C./cm from 1150° C. to 850° C. at feeding rate of 10 mm/h while holdingthe joined A₁, A₂, A₃ at a low temperature side and the joined B, C, Dat a high temperature side.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the plate face structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 4

An ingot of silicon steel containing C: 0.037%, S: 3.00%, sol Al:0.028%, N: 0.0085%, S: 0.031% was hot rolled to obtain a hot rolledsheet of 3 mm in thickness, which was first cold rolled at a reductionof 30% and then annealed at 1100° C. in H₂ for 5 minutes. Next, thesheet was cold rolled at a reduction of 85.7% to a final thickness of0.3 mm, heated from 200° C. to 700° C. at a temperature rising rate of20° C./h and subjected to decarburization annealing at 800° C. in a wethydrogen for 5 minutes, from which a piece of 150 w×300 l mm containinga large amount of primary recrystallized grain boundary was cut out as atreating sheet at high energy state A.

On the other hand, a plate-like single crystal comprising 3.5% of Si andthe balance being Fe and inevitable impurities in which (110) face ascoincident with plate face was used as a seed plate B.

Then, section of A perpendicular to both rolling direction and rollingface as well as (001) face of B perpendicular to plate face werefinished into a mirror surface of Ra≦0.2 μm by Emery polishing. After Snfilm of 1.0 μm in thickness was plated onto the polished surface, asolution of SnCl₂ +ethanol was applied to the plated surface and heatedto 350° C. at both surfaces and then the plated surfaces of A, B werecontacted with each other and the plated surface of B was closely joinedto the plated surface of A while applying a supersonic wave to the jointface and a compressive stress of 5 g/mm² thereto, which was heated byfeeding into a temperature tilting furnace having a temperature gradientof 10° C./cm from 1200° C. to 950° C. in N₂ atmosphere at a feeding rateof 10 mm/h while holding A at low temperature side and B at hightemperature side.

In each of the thus obtained joined bodies, no grain boundary wasobserved at A, B and the joint face as measured from the crystalstructure of plate face at the joint interface, and also the joined Aand B were confirmed to form the same crystal body from the measuredresults of crystalline orientation.

Moreover, when the same three steel sheets as in A before the treatmentwere subjected to the same tilting annealing without joining accordingto the invention, B₁₀ values of the resulting steel sheets were as lowas 1.70, 1.85, 1.95(T), respectively, and also the scattering was large,while B₁₀ value of the joined body obtained according to the inventionwas as high as 2.00(T).

Example 5

An ingot of silicon steel containing C: 0.035%, S: 3.00%, Se: 0.020% washot rolled to obtain a hot rolled sheet of 2.5 mm in thickness. After asheet of 0.4 mm in thickness was finished by cold rolling, it wasannealed at 950° C. in dry N₂ for 10 minutes. Thereafter, a sheet of 0.3mm in thickness was finished by cold rolling and decarburized at 820° C.in a wet hydrogen for 5 minutes and 2.75% strain was introducedthereinto under tension, from which a piece of 300 l×1000 W mm was cutout as a treating sheet at high energy state A.

On the other hand, a plate-like single crystal comprising 3.5% of Si andthe balance being Fe and inevitable impurities in which (110) face ascoincident with plate face was used as a seed plate B.

Then, section of A parallel to the rolling direction and perpendicularto the rolling face as well as (110) face of B perpendicular to plateface were finished into a mirror surface of Ra≦0.2 μm by Emerypolishing. After Sn film of 1.0 μm in thickness was plated onto thepolished surface, a solution of SnCl₂ +ethanol was applied to the platedsurface and the plated faces of A, B were closely joined by rubbingwhile heating to 350° C. and applying a supersonic wave. While the steelsheet was curved by giving a curvature of D=750 mm in l direction, thejoined body was heated by feeding into a temperature tilting furnacehaving a temperature gradient of 20° C./cm from 1500° C. to 850° C. inN₂ atmosphere at a feeding rate of 10 mm/h while applying a compressivestress of 15 g/mm² to the joint face and holding A at low temperatureside and B at high temperature side.

In each of the thus obtained joined bodies, no grain boundary wasobserved at A, B and the joint face as measured from the crystalstructure of plate face at the joint interface, and also the joined Aand B were confirmed to form the same crystal body from the measuredresults of crystalline orientation.

In five samples obtained by applying MgO as a separator to the crystalbody and annealing at 1200° C. in H₂ for 5 hours, the B₁₀ value was1.99˜2.02 (T) and the W_(17/50) value was 0.85˜0.95 (W/kg), and theiraverage magnetic properties were B₁₀ : 2. 01 (T), W_(17/50) : 0.90(W/kg).

Example 6

From a block-like coarse grain comprising 2% of Si and the balance beingFe and inevitable impurities were cut out three single crystal plates of0.5 mm thickness and 10 mm×30 mm by electric arc method so as to renderthe plate face into (100), (110), (111) as seed plates B, C, D.

On the other hand, a steel ingot comprising C: 0.022%, Si: 0.37%, Mn:0.43%, P: 0.019%, S: 0.011%, Cu: 0.11%, Ni: 0.20%, Cr: 17.50%, Al:0.005%, N: 0.025% and the balance being Fe and inevitable impurities washot rolled to obtain a hot rolled sheet of 2 mm in thickness, which wassubjected to a combination of cold rollings in the hot rolling directionand a direction perpendicular thereto to obtain a cold rolled sheet of0.5 mm in thickness. Then, the sheet was annealed at 1000° C. in N₂ for3 hours and 2.5% strain was introduced thereinto under tension to renderinto a high energy state as compared with the seed plates, from whichthree sheets of 20 mm×30 mm were cut out as treating sheets A₁, A₂, A₃.

Then, each plate face of A₁, A₂, A₃, B, C, D was finished into a mirrorsurface of Ra≦0.2 μm by Emery polishing and chemical polishing. After analloy film of Sn and Pb of 1.5 μm in thickness was coated onto thepolished face by vacuum deposition, the coated face of each of B, C, Dwas closely joined to the plated face of each of A₁, A₂, A₃, which washeated at 1200° C. in Ar atmosphere for 100 hours while applying acompressive stress of 5 g/mm² to the joint face.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the sectional structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 7

From a coarse single crystal grain obtained by introducing strain intoMo block having a purity of 99.9% and annealing were cut out threesingle crystal plates 0.5 mm thickness and 10 mm×30 mm by electric arcmethod so as to render the plate face into (100), (110), (111) as seedplates B, C, D.

On the other hand, a steel ingot comprising Ca: 0.0025% and the balancebeing Mo and inevitable impurities was hot rolled to obtain a hot rolledsheet of 2 mm in thickness, which was subjected to a combination of coldrollings in the hot rolling direction and a direction perpendicularthereto to obtain a cold rolled sheet of 0.5 mm in thickness, from whichthree square sheets of 20 mm×30 mm were cut out as treating sheets A₁,A₂, A₃.

Then, each plate face of A₁, A₂, A₃, B, C, D was finished into a mirrorsurface of Ra≦0.2 μm by Emery polishing. After Fe film of 2 μm inthickness was plated onto the polished face, the plated face of each ofB, C, D was closely joined to the plated face of each of A₁, A₂, A₃,which was heated at 1200° C. in Ar atmosphere for 1 hour while applyinga compressive stress of 5 g/mm² to the joint face and annealed at 1250°C. in Ar atmosphere for 50 hours after the releasing of compressivestress.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the plate face structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 8

From a block-like coarse single crystal grain comprising 23% of Fe andthe balance being Ni and inevitable impurities were cut out three singlecrystal plates of 0.5 mm thickness and 10 mm×30 mm by electric arcmethod so as to render the plate face into (100), (110), (111) as seedplates B, C, D.

On the other hand, a steel ingot comprising Fe: 22.9% and the balancebeing Ni and inevitable impurities was hot rolled to obtain a flat sheetof 13 mm in thickness. After the thickness was reduced to 9 mm by coldrolling, the sheet was annealed at 800° C. for 10 minutes and subjectedto a combination of cold rollings in the hot rolling direction and thedirection perpendicular thereto to obtain a cold rolled sheet of 0.5 mmin thickness, from which three square sheets of 20 mm×30 mm were cut outas treating sheets A₁, A₂, A₃.

Then, each plate face of A₁, A₂, A₃, B, C, D was finished into a mirrorsurface of Ra≦0.2 μm by Emery polishing. After Sn film of 1 μm inthickness was coated onto the polished face by vacuum deposition, thecoated face of each of B, C, D was closely joined to the coated face ofeach of A₁, A₂, A₃, which was annealed at 1050° C. in Ar atmosphere for24 hours while applying a compressive stress of 10 g/mm² to the jointface.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the plate face structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 9

From a coarse single crystal grain obtained by introducing strain intoCu block having a purity of 99.9% and annealing were cut out threesingle crystal plates of 0.3 mm thickness and 10 mm×30 mm by electricarc method so as to render the plate face into (100), (110), (111) asseed plates B, C, D.

On the other hand, a square sheet of 30 mm thickness and 40 mm×50 mm wascut out from a commercially available pure copper (containing O:0.0009%, P: 0.0003%, S: 0.001% as an impurity), which was finished to acold rolled sheet of 0.3 mm in thickness while rotating the cold rollingdirection by 90° every pass, from which three square sheets of 20 mm×30mm were cut out as treating sheets A₁, A₂, A₃.

Then, each plate face of A₁, A₂, A₃, B, C, D was finished into a mirrorsurface of Ra≦0.2 μm by Emery polishing. After an alloy film of Sn-Bi of1 μm in thickness was coated onto the polished face by vacuumdeposition, the coated face of each of B, C, D was closely joined to thecoated face of each of A₁, A₂, A₃, which was annealed at 1000° C. undervacuum of 10⁻² Torr for 24 hours while applying a compressive stress of2 g/mm² to the joint face.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the plate face structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 10

From a coarse single crystal grain obtained by introducing strain intoAl block having a purity of 99.9% and annealing were cut out threesingle crystal plates of 0.3 mm thickness and 10 mm×30 mm by electricarc method so as to render the plate face into (100), (110), (111) asseed plates B, C, D.

On the other hand, a square sheet of 30 mm thickness and 40 mm×50 mm wascut out from a commercially available pure Al (containing Fe: 0.003%,Si: 0.004% as an impurity), which was finished to a cold rolled sheet of0.3 mm in thickness while rotating the cold rolling direction by 90°every pass, from which three square sheets of 20 mm×30 mm were cut outas treating sheets A₁, A₂, A₃.

Then, each plate face of A₁, A₂, A₃, B, C, D was finished into a mirrorsurface of Ra≦0.2 μm by Emery polishing. After an alloy film of Al-Si of2 μm in thickness was coated onto the polished face by vacuumdeposition, the coated face of each of B, C, D was closely joined to thecoated face of each of A₁, A₂, A₃, which was heated at 600° C. in N₂while applying a compressive stress of 10 g/mm² to the joint face andapplying a supersonic wave and annealed at 625° C. under vacuum of 10⁻²Torr for 24 hours while applying a compressive stress of 2 g/mm² to thejoint face.

In each of the thus obtained joined bodies, no border or grain boundarywas observed at the joint face as measured from the plate face structureat the joint interface, and also each of the joined A₁, A₂, A₃ wasconfirmed to be a crystal body having the same orientation as in each ofB, C, D from the measured results of crystalline orientation.

Example 11

An ingot of silicon steel containing C: 0.042%, Si: 3.25%, Mn: 0.060%,S: 0.002%, Se: 0.019%, O: 0.005% and the balance being Fe and inevitableimpurities was heated to 1350° C. and hot rolled to obtain a hot rolledsheet of 2.5 mm in thickness. Then, the sheet was subjected to a firstcold rolling to an intermediate thickness of 0.4 mm and a second coldrolling to a thickness of 0.3 mm through an intermediate annealing at950° C. in dry N₂ for 10 minutes. Thereafter, the sheet was subjected todecarburization and primary recrystallization annealing at 820° C. in awet hydrogen for 5 minutes and 2.75% strain was introduced into thesteel sheet under tension, from which four specimens of l=300 mm, W=160mm were cut out as A1, A2, A3, A4.

On the other hand, an ingot of silicon steel having the same compositionexcept O: 0.0015% was treated in the same manner as in A to obtainspecimens B1, B2, B3, B4.

Furthermore, a plate-like single crystal comprising 3.5% of Si, and thebalance being Fe and inevitable impurities and having α=0° and β=2° wasused as a seed plate C.

Each plate face of A1˜A4, B1˜B4 and C was finished into a mirror surfaceby chemical polishing and subjected to an argon sputtering under asuperhigh vacuum (10⁻¹⁰ Torr). Thereafter, each of A1, A2, B1, B2 wasclosely joined with C so that the sputtered faces were piled only at awidth of 5 mm in a direction perpendicular to the rolling direction soas to coincide the rolling direction with <001> axis of C, which was fedinto a temperature tilting furnace having a temperature gradient of 10°C./cm between 1150˜850° C. at a feeding rate of 10 mm/h while holdingA1, A2, B1, B2 at low temperature side and C at high temperature sideand applying a compressive load of 10 g/mm² to the joint face, and alsoeach of A3, A4, B3, B4 was fed into the same furnace without joining toC while holding the end face perpendicular to the rolling direction athigh temperature side, during which the heating was conducted under asuperhigh vacuum.

As a result of the examination on the crystal structure of each of thethus obtained joined bodies, all of A3, A4, B3, B4 were coarsepolycrystal bodies, while each of A1, A2, B1, B2 was single crystal bodyand had no grain boundary even at the joint face, and also it has beenconfirmed from the measured results of crystalline orientation that eachof the specimens A1, A2, B1, B2 forms a crystal body having the sameorientation as in the seed plate C.

Furthermore, B₁₀ values of A1, A2, A3, A4 were 1.99, 1.97, 1.68, 1.55(T), respectively, and B₁₀ values of B1, B2, B3, B4 were 2.00, 1.98,1.70, 1.62 (T), respectively. Thus, even if the oxygen amount in the rawmaterial is large or small, the B₁₀ value is largely improved by joininga secondary recrystallized seed material.

After the application of MgO as a separator, A1, A2, B1, B2, weresubjected to a purification annealing at 1200° C. in H₂ for 5 hours anda tension coating was applied thereto, and then the magnetic propertieswere measured to obtain results as shown in the following Table 3.

                  TABLE 3                                                         ______________________________________                                                  B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                            ______________________________________                                        A1          2.00    0.83                                                      A2          1.98    0.88                                                      B1          2.01    0.80                                                      B2          1.99    0.83                                                      ______________________________________                                    

Example 12

An ingot of silicon steel containing C: 0.042%, Si: 3.25%, Mn: 0.060%,S: 0.002%, Se: 0.019%, O: 0.005% and the balance being Fe and inevitableimpurities was heated to 1350° C. and hot rolled to obtain a hot rolledsheet of 2.5 mm in thickness. Then, the sheet was subjected to a firstcold rolling to an intermediate thickness of 0.4 mm and a second coldrolling to a thickness of 0.3 mm through an intermediate annealing at950° C. in dry N₂ for 10 minutes. Thereafter, the sheet was subjected todecarburization and primary recrystallization annealing at 820° C. in awet hydrogen for 5 minutes and 2.75% strain was introduced into thesteel sheet under tension, from which four specimens of l=300 mm, W=160mm were cut out as A1, A2, A3, A4.

On the other hand, an ingot of silicon steel having the same compositionexcept O: 0.0015% was treated in the same manner as in A to obtainspecimens B1, B2, B3, B4.

Furthermore, a plate-like single crystal comprising 3.5% of Si and thebalance being Fe and inevitable impurities and having α=0° and β=2° wasused as a seed plate C.

Each sectional face of A1˜A4, B1˜B4 parallel to the rolling directionand perpendicular to the rolling face and (110) face of C perpendicularto plate face were finished into a mirror surface of Ra<0.2 μm by Emerypolishing. After Sn film of 1.0 μm was plated on each of the polishedsurfaces, each plated surface of A1, A2, B1, B2 was closely joined withthe plated surface of C. Then, these joined bodies as well as non-joinedbodies were heated by feeding into a temperature tilting furnace havinga temperature gradient of 10° C./cm between 1150˜850° C. at a feedingrate of 10 mm/h while applying a compressive load of 15 g/mm² to thejoint face and holding A1, A2, B1, B2 at low temperature side and C athigh temperature side and holding the plated surfaces of A3, A4, B3, B4not joining with C at high temperature side.

As a result of the examination on the crystal structure of each of thethus obtained joined bodies, all of A3, A4, B3, B4 were coarsepolycrystal bodies, while each of A1, A2, B1, B2 was single crystal bodyand had no grain boundary even at the joint face, and also it has beenconfirmed from the measured results of crystalline orientation that eachof the joining materials A1, A2, B1, B2 forms a crystal body having thesame orientation as in the seed plate C.

Furthermore, B₁₀ values of A1, A2, A3, A4 were 1.95, 1.99, 1.70, 1.62(T), respectively, and B₁₀ values of B1, B2, B3, B4 were 1.99, 1.97,1.75, 1.85 (T), respectively. Thus, even if the oxygen amount in the rawmaterial is large or small, the B₁₀ value is largely improved by joininga secondary recrystallized seed material.

After the application of MgO as a separator, A1, A2, B1, B2, weresubjected to a purification annealing at 1200° C. in H₂ for 5 hours, andthen the magnetic properties were measured to obtain results as shown inthe following Table 4.

                  TABLE 4                                                         ______________________________________                                                  B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                            ______________________________________                                        A1          1.97    0.90                                                      A2          2.00    0.85                                                      B1          2.00    0.82                                                      B2          1.98    0.85                                                      ______________________________________                                    

Example 13

An ingot of silicon steel containing C: 0.060%, Si: 3.25%, Mn: 0.060%,S: 0.002%, sol Al: 0.015%, N: 0.0085% and the balance being Fe andinevitable impurities was heated to 1250° C. and hot rolled to obtain ahot rolled sheet of 1.9 mm in thickness. Then, the sheet was annealed at1120° C. for 2 minutes, finished to a thickness of 0.20 mm by coldrolling and subjected to decarburization and primary recrystallizationannealing at 820° C. in a wet hydrogen for 5 minutes, from which fourspecimens of l=300 mm, W=160 mm were cut out as A1, A2, A3, A4.

On the other hand, an ingot of silicon steel having the same compositionexcept Al: 0.050% was treated in the same manner as in A to obtainspecimens B1, B2, B3, B4.

Furthermore, a plate-like single crystal comprising 3.0% of Si and thebalance being Fe and inevitable impurities and having α=0° and β=2.5°was used as a seed plate C.

Each plate face of A1˜A4, B1˜B4 and C was finished into a mirror surfaceby chemical polishing and subjected at the mirror surface to an argonsputtering under a superhigh vacuum (10⁻¹⁰ Torr). Thereafter, each ofA1˜A4, B1˜B4 was closely joined with C so that the sputtered faces werepiled only at a width of 5 mm in a direction perpendicular to therolling direction so as to coincide the rolling direction with <001>axis of C, which was heated under the following conditions whileapplying a compressive load of 10 g/mm² to the joint face. Each of A1,A2, B1, B2 was annealed in a uniform furnace of N₂ atmosphere at 990° C.for 24 hours. On the other hand, each of A3, A4, B3, B4 was heated byfeeding into a temperature tilting furnace having a temperature gradientof 5° C./cm between 1150˜850° C. at a feeding rate of 10 mm/h whileholding A3, A4, B3, B4 at low temperature side and C at high temperatureside.

As a result of the examination on the crystal structure of each of thethus obtained joined bodies, each of A1, A2, B1, B2 partly contained acoarse polycrystal body, while each of A3, A4, B3, B4 was a singlecrystal body. Furthermore, no grain boundary was observed at the jointface in all of A1˜A4, B1˜B4, and also it has been confirmed from themeasured results of crystalline orientation that they form a crystalbody having the same orientation as in the seed plate C around the jointface.

After the application of MgO as a separator, A1˜A4, B1˜B4, weresubjected to a purification annealing at 1200° C. in H₂ for 20 hours,and then the magnetic properties were measured to obtain results asshown in the following Table 5.

                  TABLE 5                                                         ______________________________________                                        B.sub.10 (T)                                                                           W.sub.17/50 (W/kg) B.sub.10 (T)                                                                        W.sub.17/50 W/kg)                           ______________________________________                                        A1  2.00     0.80         B1  1.98  0.86                                      A2  1.98     0.85         B2  1.99  0.85                                      A3  1.99     0.83         B3  1.97  0.87                                      A4  1.97     0.88         B4  1.95  0.89                                      ______________________________________                                    

Thus, even if the A1 amount in the raw material is small or large, oreven if the secondary recrystallization annealing is carried out in thetemperature tilting furnace or the temperature uniform furnace, the veryhigh B₁₀ value and the low iron loss value are obtained.

Example 14

An ingot of silicon steel containing C: 0.060%, Si: 3.25%, Mn: 0.060%,S: 0.022%, sol Al: 0.015%, N: 0.0085% and the balance being Fe andinevitable impurities was heated to 1250° C. and hot rolled to obtain ahot rolled sheet of 1.9 mm in thickness. Then, the sheet was annealed at1120° C. for 2 minutes, finished to a thickness of 0.20 mm by coldrolling and subjected to decarburization and primary recrystallizationannealing at 820° C. in a wet hydrogen for 5 minutes, from which fourspecimens of l=300 mm, W=160 mm were cut out as A1, A2, A3, A4.

On the other hand, an ingot of silicon steel having the same compositionexcept Al: 0.050% was treated in the same manner as in A to obtainspecimens B1, B2, B3, B4.

Furthermore, a plate-like single crystal comprising 3.0% of Si and thebalance being Fe and inevitable impurities and having α=0° and β=2.5°was used as a seed plate C.

Each sectional face of A1˜A4, B1˜B4 parallel to the rolling directionand perpendicular to the rolling face as well as (110) face of Cperpendicular to plate face were finished into a mirror surface ofRa<0.2 μm by Emery polishing. After Sn film of 1.0 μm was plated ontoeach polished surface, each plated surface of A1˜A4, B1˜B4 was closelyjoined with the plated surface of C, which was heated under thefollowing conditions while applying a compressive load of 10 g/mm² tothe joint face. Each of A1, A2, B1, B2 was annealed in a uniform furnaceof N₂ atmosphere at 990° C. for 24 hours. On the other hand, each of A3,A4, B3, B4 was heated by feeding into a temperature tilting furnacehaving a temperature gradient of 5° C./cm between 1150˜850° C. at afeeding rate of 10 mm/h while holding A3, A4, B3, B4 at low temperatureside and C at high temperature side.

As a result of the examination on the crystal structure of each of thethus obtained joined bodies, each of A1, A2, B1, B2 partly contained acoarse polycrystal body, while each of A3, A4, B3, B4 was a singlecrystal body. Furthermore, no grain boundary was observed at the jointface in all of A1˜A4, B1˜B4, and also it has been confirmed from themeasured results of crystalline orientation that they form a crystalbody having the same orientation as in the seed plate C around the jointface.

After the application of MgO as a separator, A1˜A4, B1˜B4, weresubjected to a purification annealing at 1200° C. in H₂ for 20 hours,and then the magnetic properties were measured to obtain results asshown in the following Table 6.

                  TABLE 6                                                         ______________________________________                                        B.sub.10 (T)                                                                           W.sub.17/50 (W/kg) B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                          ______________________________________                                        A1  1.99     0.82         B1  1.98  0.85                                      A2  1.97     0.88         B2  1.96  0.89                                      A3  1.98     0.83         B3  2.00  0.82                                      A4  2.02     0.80         B4  2.01  0.80                                      ______________________________________                                    

Thus, even if the A1 amount in the raw material is small or large, oreven if the secondary recrystallization annealing is carried out in thetemperature tilting furnace or the temperature uniform furnace, the veryhigh B₁₀ value is obtained.

Example 15

An ingot of silicon steel containing C: 0.085%, Si: 3.00%, Mn: 0.080%,S: 0.015%, sol Al: 0.030%, N: 0.0085% and the balance being Fe andinevitable impurities was heated to 1350° C. and immediately hot rolledto a thickness of 0.35 mm. Then, two sheets having a length: 150 mm anda width: 50 mm were cut out and decarburized at 750° C. in wet hydrogenfor 3 hours as A1, A2.

On the other hand, two single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.35 mm, a length: 150 mm, a width: 5 mm, α=0° and β=2° were provided asB1, B2.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface of Ra<0.1 μm by Emery polishing andchemical polishing, ion sputtering. Thereafter, the mirrored surfaces ofA1 and B1 were closed with each other, which were heated from 1000° C.to 1200° C. at a temperature rising rate of 5° C./h under vacuum of 10⁻⁶Torr. On the other hand, Sn of 1 μm in thickness as an insert member wasdeposited onto the mirrored surfaces of A2 and B2, which was heated at asurface closed state in N₂ having a dew point of -50° C. in the samemanner as in A1, B1. After MgO was applied as a separator, it wassubjected to a purification annealing at 1200° C. in H₂ for 20 hours andfurther a tension coating was applied, and thereafter the magneticproperties of A were measured to obtain results as shown in Table 7.

                  TABLE 7                                                         ______________________________________                                        Presence or absence                                                                        B.sub.10 (T)  W.sub.17/50 (W/kg)                                 of insert member                                                                           presence absence  presence                                                                             absence                                 ______________________________________                                        Magnetization in                                                                           2.01     1.99     0.95   0.97                                    the same direction                                                            as in hot rolling                                                             ______________________________________                                    

Example 16

An ingot of silicon steel having the same composition as in Example 1was heated to 1350° C. and hot rolled to a thickness of 0.35 mm. Then,two square specimens having a length: 200 mm and a width: 50 mm were cutout therefrom, which were annealed at 1050° C. in dry H₂ for 3 minutesand decarburized at 750° C. in a wet hydrogen for 1 hour to obtain A3,A4.

On the other hand, two single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.35 mm, a length: 200 mm, a width: 5 mm, α=0° and β=2° were provided asB3, B4.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface of Ra<0.1 μm by Emery polishing andchemical polishing, ion sputtering. After Sn of 0.5 μm in thickness wasformed onto the mirrored surfaces of A4, B4 by ion coating. the mirroredsurfaces of A3 and B3 as well as the coated surfaces of A4 and B4 wereclosed with each other and a compressive load: 7 g/mm² was applied tothe joint face, which were heated under vacuum of 10⁻⁶ Torr in case ofA3, B3 not coated with Sn or in N₂ having a dew point of -10° C. in caseof A4, B4 coated with Sn by feeding into a temperature tilting furnacehaving a temperature gradient of 5° C./cm between 1150° C.˜900° C. at afeeding rate of 10 mm/h while holding A at low temperature side and B athigh temperature side.

After MgO was applied as a separator, it was subjected to a purificationannealing at 1200° C. in H₂ for 20 hours and further a tension coatingwas applied, and thereafter the magnetic properties were measured toobtain results as shown in Table 8.

                  TABLE 8                                                         ______________________________________                                        Presence or absence                                                                        B.sub.10 (T)  W.sub.17/50 (W/kg)                                 of insert member                                                                           presence absence  presence                                                                             absence                                 ______________________________________                                        Magnetization in                                                                           2.03     1.99     0.91   0.94                                    the same direction                                                            as in hot rolling                                                             ______________________________________                                    

Example 17

An ingot of silicon steel comprising C: 0.175%, Si: 3.01%, Mn: 0.075%,Al: 0.035%, N: 0.0111%, S: 0.011%, Se: 0.007%, Te: 0.005%, Sb: 0.007%and the balance being Fe and inevitable impurities was heated at 1350°C. for 1 hour and hot rolled to a thickness of 1.9 mm. Then, the sheetwas cold rolled to a thickness of 0.23 mm, from which two squarespecimens having a length: 150 mm and a width: 50 mm were cut out andheated at a temperature rising rate of 20° C./h between 200° C.˜700° C.and subjected to decarburization annealing at 750° C. in a wet hydrogenfor 3 hours to obtain a raw material A.

Thereafter, the same procedure as in Example 15 was repeated to obtainresults as shown in Table 9.

                  TABLE 9                                                         ______________________________________                                        Insert member  B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        presence       2.02    0.67                                                   absence        2.01    0.68                                                   ______________________________________                                    

Example 18

An ingot of silicon steel comprising C: 0.049%, Si: 3.35%, Mn: 0.075%,S: 0.018%, Al: 0.032%, N: 0.0085% and the balance being Fe andinevitable impurities was heated to 1350° C. and hot rolled to athickness of 1.15 mm. Then, the sheet was subjected to decarburizationannealing at 725° C. in wet H₂ for 3 hours and then cold rolled to athickness of 0.20 mm, from which four square specimens having a length:150 mm and a width: 50 mm were cut out. Among these specimens, twospecimens were subjected to primary recrystallization annealing at 850°C. for 5 minutes as A1, A2 and the remaining specimens were notsubjected thereto as A3, A4.

On the other hand, four single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.23 mm, a length: 150 mm, a width: 5 mm, α=0° and β=2° were provided asB1, B2, B3, B4.

The same procedure as in Example 16 was repeated to obtain results asshown in Table 10.

                  TABLE 10                                                        ______________________________________                                        Primary                                                                       recrystalliza-                                                                tion annealing                                                                          Insert member                                                                              B.sub.10 (T)                                                                           W.sub.17/50 (W/kg)                            ______________________________________                                        presence  presence     2.015    0.72                                                    absence      2.010    0.74                                          absence   presence     2.010    0.73                                                    absence      2.007    0.75                                          ______________________________________                                    

Example 19

An ingot of silicon steel comprising C: 0.023%, Si: 3.0%, Mn: 0.040%,Se: 0.011%, Al: 0.051%, N: 0.0105%, and the balance being Fe andinevitable impurities was heated to 1225° C. and immediately hot rolledto a thickness of 0.23 mm. Then, two square sheets having a length: 200mm and a width: 50 mm were cut out therefrom and subjected todecarburization annealing at 850° C. in a wet hydrogen for 5 minutes asA3, A4.

On the other hand, two single crystal plates having the same compositionas in the above hot rolled sheet, a thickness: 0.23 mm, a length: 2.00mm, a width: 5 mm, α=0° and β=2° were provided as B3, B4.

The same procedure as in Example 16 was repeated to obtain results asshown in Table 11.

                  TABLE 11                                                        ______________________________________                                        Insert member  B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        presence       2.02    0.67                                                   absence        2.01    0.68                                                   ______________________________________                                    

Example 20

An ingot of silicon steel comprising C: 0.205%, Si: 3.42%, Mn: 0.035%,Al: 0.032%, N: 0.0095%, Se: 0.008% and the balance being Fe andinevitable impurities was heated to 1225° C. for 1 hour and hot rolledto a thickness of 0.30 mm. Then, two square sheets having a length: 200mm and a width: 50 mm were cut out therefrom and annealed at 1100° C. ina dry N₂ for 1 minute and thereafter annealed at 725° C. in a wethydrogen for 5 hours to obtain a raw material A.

Thereafter, the same procedure as in Example 16 was repeated to obtainresults as shown in Table 12.

                  TABLE 12                                                        ______________________________________                                        Insert member  B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        presence       2.02    0.78                                                   absence        2.00    0.79                                                   ______________________________________                                    

Example 21

An ingot of silicon steel comprising C: 0.083%, Si: 3.05%, Mn: 0.045%,Se: 0.012%, Al: 0.040%, N: 0.0090% and the balance being Fe andinevitable impurities was heated to 1200° C. for 1 hour and hot rolledto a thickness of 1.9 mm. Then, the sheet was cold rolled to a thicknessof 0.30 mm, from which two square sheets having a length: 150 mm and awidth; 50 mm were cut out and subjected to decarburization annealing at725° C. in a wet hydrogen for 1 hour to obtain a raw material A.

Thereafter, the same procedure as in Example 15 was repeated to obtainresults as shown in Table 13.

                  TABLE 13                                                        ______________________________________                                        Insert member  B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        presence       2.03    0.82                                                   absence        2.01    0.83                                                   ______________________________________                                    

Example 22

An ingot of silicon steel comprising C: 0.085%, Si: 4.0%, Mn: 0.050%, S:0.013%, Al: 0.035%, N: 0.0080% and the balance being Fe and inevitableimpurities was heated to 1200° C. and hot rolled to a thickness of 1.15mm. Then, the sheet was subjected to decarburization annealing at 725°C. in wet H₂ for 3 hours and then cold rolled to a thickness of 0.20 mm,from which four square specimens having a length: 150 mm and a width: 50mm were cut out. Among these specimens, two specimens were subjected todecarburization and primary recrystallization annealing at 850° C. for 5minutes as A1, A2 and the remaining specimens were not subjected theretoas A3, A4.

On the other hand, four single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.23 mm, a length: 150 mm, a width: 5 mm, α=0° and β=2° were provided asB1, B2, B3, B4.

The same procedure as in Example 16 was repeated to obtain results asshown in Table 14.

                  TABLE 14                                                        ______________________________________                                        Primary                                                                       Recrystalliza-                                                                tion annealing                                                                          Insert member                                                                              B.sub.10 (T)                                                                           W.sub.17/50 (W/kg)                            ______________________________________                                        presence  presence     1.970    0.83                                                    absence      1.965    0.85                                          absence   presence     1.967    0.84                                                    absence      1.972    0.82                                          ______________________________________                                    

Example 23

A sheet bar (thickness: 30 mm) of silicon steel comprising C: 0.125%,Si: 3.0%, Mn: 0.080%, Al: 0.030%, N: 0.0085%, Sb: 0.030% and the balancebeing Fe and inevitable impurities and casted through a belt caster washeated at 950° C. for 1 hour and hot rolled to a thickness of 1.15 mm.Then, the sheet was subjected to decarburization annealing at 725° C. inwet hydrogen for 5 hours and cold rolled to a thickness of 0.20 mm, fromwhich six square sheets having a length: 150 mm and a width: 50 mm werecut out. Among these specimens, three sheets were subjected to primaryrecrystallization annealing at 850° C. for 5 minutes as A1, A2, A3, andthe remaining sheets were not subjected thereto as A4, A5, A6.

On the other hand, six single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.23 mm, a length: 150 mm, a width: 5 mm, α=0° and β=2° were provided asB1, B2, B3, B4, B5, B6.

Then, three sets of A and B polished into mirror surface in the samemanner as in Example 16 were provided in the presence or absence ofprimary recrystallization annealing. After S, Sb, Zn of 0.5 μm inthickness were formed on the mirrored surfaces of each set by ioncoating, the coated surfaces of each set were closed with each other.

The same procedure as in Example 16 was repeated to obtain results asshown in Table 15.

                  TABLE 15                                                        ______________________________________                                        Primary                                                                       recrystalliza-                                                                tion annealing                                                                          Insert member                                                                              B.sub.10 (T)                                                                           W.sub.17/50 (W/kg)                            ______________________________________                                        presence  S            2.01     0.71                                                    Sb           2.00     0.73                                                    Zn           2.02     0.70                                          absence   S            2.01     0.72                                                    Sb           2.00     0.74                                                    Zn           2.01     0.73                                          ______________________________________                                    

Example 24

An ingot of silicon steel comprising C: 0.040%, Si: 3.10%, Mn: 0.055%,S: 0.012%, sol Al: 0.020%, N: 0.0095% and the balance being Fe andinevitable impurities was heated at 1200° C. and hot rolled to athickness of 1.15 mm.

Then, the sheet was subjected to decarburization annealing at 725° C. ina wet hydrogen for 5 hours and cold rolled to a thickness of 0.20 mm,from which four square sheets having l=150 mm and W=50 mm were cut outas A1, A2, A3, A4. Then, only A2, A4 were subjected to primaryrecrystallization annealing at 800° C. in dry H₂ for 2 minutes.

On the other hand, four single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.23 mm, a length: 150 mm, a width: 5 mm, α=0° and β=2° were provided asB1, B2, B3, B4.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface of Ra<0.1 μm by Emery polishing andchemical polishing, ion sputtering. After Sn of 1 μm in thickness wasformed onto the mirrored surfaces of B1, B2 by ion coating, the mirroredsurface and the coated surface of A1 and B1 as A2 and B2 were closedwith each other so as to coincide the lengthwise directions and joinedby heating at 900° C. in a dry N₂. Furthermore, the lengthwisedirections of A3 and B3 as well as A4 and B4 were coincided with eachother so as to overlap the ion sputtered mirror surfaces only at a widthof 5 mm in the rolling direction and direction perpendicular thereto andjoined by heating at 900° C. under vacuum of 10⁻⁸ Torr. While acompressive load: 7 g/mm² was applied to the joint face, the joinedsheets were heated by feeding into a temperature tilting furnace havinga temperature gradient of 5° C./cm between 1150° C.˜900° C. at a feedingrate of 10 mm/h in N₂ having a dew point of -50° C. while holding A atlow temperature side and B at high temperature side.

After MgO was applied as a separator, it was subjected to a purificationannealing at 1200° C. in H₂ for 20 hours and further a tension coatingwas applied, and thereafter the magnetic properties were measured toobtain the following results.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.013   0.74                                                     A2-B2        2.022   0.76                                                     A3-B3        2.017   0.75                                                     A4-B4        2.015   0.77                                                     ______________________________________                                    

Thus, when the decarburization was carried out prior to the rolling,even if the primary recrystallization annealing before the finishannealing was omitted, or even if the atmosphere for the primaryrecrystallization annealing was dry H₂, good magnetic properties wereobtained.

Example 25

An ingot of silicon steel comprising C: 0.003%, Si: 3.2%, Mn: 0.010%, S:0.005%, N: 0.0085%, sol Al: 0.035% and the balance being Fe andinevitable impurities was heated at 1180° C. and hot rolled to athickness of 0.30 mm. Then, four square sheets having l=150 mm and W=50mm were cut out therefrom as A1, A2, A3, A4. Next, only A2, A4 weresubjected to primary recrystallization annealing at 850° C. in dry H₂for 1 minute.

The same procedure as in Example 24 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.015   0.95                                                     A2-B2        2.020   0.97                                                     A3-B3        2.019   0.96                                                     A4-B4        2.018   0.98                                                     ______________________________________                                    

Example 26

An ingot of silicon steel comprising C: 0.003%, Si: 3.25%, Mn: 0.05%, S:0.010%, N: 0.080%, Al: 0.050% and the balance being Fe and inevitableimpurities was heated at 1200° C. and hot rolled to a thickness of 2.3mm. Then, the sheet was annealed at 950° C. in a dry N₂ for 2 minutesand cold rolled to a thickness of 0.3 mm, from which four square sheetshaving l=150 mm and W=50 mm were cut out as A1, A2, A3, A4. Next, onlyA2, A4 were subjected to primary recrystallization annealing at 850° C.in dry H₂ for 1 minute.

The same procedure as in Example 24 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.013   0.98                                                     A2-B2        2.011   0.99                                                     A3-B3        2.012   0.97                                                     A4-B4        2.010   0.98                                                     ______________________________________                                    

Example 27

An ingot of silicon steel comprising C: 0.035%, Si: 3.35%, Mn: 0.045%,S: 0.008%, N: 0.0085%, Al: 0.045% and the balance being Fe andinevitable impurities was heated at 1225° C. and hot rolled to athickness of 2.3 mm. Then, the sheet was annealed at 850° C. in a wethydrogen for 15 minutes and cold rolled to a thickness of 1.15 mm.Furthermore, it was annealed at 850° C. in a wet hydrogen for 15 minutesand cold rolled to a thickness of 0.20 mm, from which four square sheetshaving l=150 mm and W=50 mm were cut out as A1, A2, A3, A4. Next, onlyA2, A4 were subjected to primary recrystallization annealing at 850° C.in wet hydrogen 3 minutes.

The same procedure as in example 24 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.013   0.75                                                     A2-B2        2.016   0.77                                                     A3-B3        2.015   0.76                                                     A4-B4        2.014   0.74                                                     ______________________________________                                    

Example 28

An ingot of silicon steel comprising C: 0.005%, Si: 3.30%, Mn: 0.055%,Se: 0.019%, Sb: 0.025%, Mo: 0.015% and the balance being Fe andinevitable impurities was heated at 1350° C. and hot rolled to athickness of 2.3 mm. Then, the sheet was cold rolled two times to athickness of 0.30 mm through an intermediate annealing at 950° C. in adry N₂ for 2 minutes, from which four square sheets having l=150 mm andW=50 mm were cut out as A1, A2, A3, A4. Next, only A2, A4 were subjectedto primary recrystallization annealing at 850° C. in dry H₂ for 1minute.

The same procedure as in Example 24 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.010   0.97                                                     A2-B2        2.008   0.96                                                     A3-B3        2.007   098                                                      A4-B4        2.009   0.95                                                     ______________________________________                                    

Example 29

An ingot of silicon steel comprising C: 0.075%, Si: 3.25%, Mn: 0.070%,S: 0.015%, Mo: 0.015%, Al: 0.025%, N: 0.0099% and the balance being Feand inevitable impurities was heated at 1300° C. and hot rolled to athickness of 2.3 mm. Then, the sheet was cold rolled to a thickness of0.30 mm, subjected to decarburization annealing at 840° C. in a wethydrogen for 10 minutes and then cold rolled to a thickness of 0.20 mm,from which four square sheets having l=150 mm and W=50 mm were cut outas A1, A2, A3, A4. Next, only A2, A4 were subjected to primaryrecrystallization annealing at 800° C. in dry H₂ for 1 minute.

On the other hand, four single crystal plates comprising 3.0% of Si andthe balance being Fe and inevitable impurities and having a thickness:0.20 mm, a length: 150 mm, a width: 5 mm, α=0° and β=2° were provided asB1, B2, B3, B4.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface by Emery polishing, chemical polishingand ion sputtering.

After Sn of 2 μm was plated onto each of A1, A2, B1, B2, a solution ofSnCl₂ +ethanol was applied to these plated surfaces, and the platedsurfaces of A1 and B1 as well as A2 and B2 were closed with each otherso as to coincide the longitudinal directions thereof and heated to 350°C. while a compressive stress of 5 g/mm² and supersonic wave wereapplied to the joint face and rubbed at the plated surfaces with eachother to closely join the plated surface of B onto the plated surface ofA. On the other hand, the ion sputtered mirror surfaces of A3 and B3 aswell as A4 and B4 were overlapped only at a width of 5 mm in the rollingdirection and the direction perpendicular thereto so as to coincide thelongitudinal directions and joined by heating at 950° C. under vacuum of10⁻⁸ Torr. After MgO containing 15% of SrSO₄ was applied as a separator,the joined body was heated in N₂ having a dew point of -30° C. at atemperature rising rate of 20° C./h and subjected to purificationannealing at 1200° C. for 24 hours and then a tension coating wasapplied, and thereafter the magnetic properties were measured to obtainthe following results.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.015   0.75                                                     A2-B2        2.020   0.77                                                     A3-B3        2.017   0.76                                                     A4-B4        2.019   0.78                                                     ______________________________________                                    

Example 30

An ingot of silicon steel comprising C: 0.003%, Si: 3.1%, Mn: 0.09%, S:0.010%, N: 0.0080%, sol Al: 0.030% and the balance being Fe andinevitable impurities was heated at 1180° C. and hot rolled to athickness of 0.30 mm. Then, the sheet was annealed at 550° C. in N₂ for24 hours, from which four square sheets having l=150 mm and W=50 mm werecut out as A1, A2, A3, A4. Next, only A3, A4 were subjected to primaryrecrystallization annealing at 850° C. in dry H₂ for 1 minute.

The same procedure as in Example 29 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.017   0.96                                                     A2-B2        2.021   0.98                                                     A3-B3        2.018   0.97                                                     A4-B4        2.019   0.99                                                     ______________________________________                                    

Example 31

An ingot of silicon steel comprising C: 0.003%, Si: 3.2%, mn: 0.10%, S:0.005%, N: 0.0085%, sol Al: 0.025% and the balance being Fe andinevitable impurities was heated at 1180° C. and hot rolled to athickness of 0.50 mm. Then, the sheet was cold rolled to a thickness of0.23 mm, from which four square sheets having l=150 mm and W=50 mm werecut out as A1, A2, A3, A4. Next, only A3, A4 were subjected to primaryrecrystallization annealing at 850° C. in dry H₂ for 1 minute.

The same procedure as in Example 29 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.015   0.81                                                     A2-B2        2.020   0.80                                                     A3-B3        2.019   0.83                                                     A4-B4        2.016   0.82                                                     ______________________________________                                    

Example 32

An ingot of silicon steel comprising C: 0.025%, Si: 3.45%, Mn: 0.20%, S:0.007%, sol Al: 0.033%, N: 0.0080% and the balance being Fe andinevitable impurities was heated at 1350° C. and hot rolled to athickness of 0.30 mm, from which four square sheets having l=150 mm andW=50 mm were cut out as A1, A2, A3, A4. Next, only A3, A4 were subjectedto primary recrystallization annealing at 850° C. in wet H₂ for 2minutes.

The same procedure as in Example 29 was repeated by adoptingdecarburization using saturated water of MgO as a separator to obtainthe following results.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.005   0.95                                                     A2-B2        2.002   0.93                                                     A3-B3        2.003   0.94                                                     A4-B4        2.006   0.92                                                     ______________________________________                                    

Example 33

An ingot of silicon steel comprising C: 0.057%, Si: 3.45%, Mn: 0.29%, S:0.003%, sol Al: 0.032%, N: 0.0090% and the balance being Fe andinevitable impurities was heated at 1350° C. and hot rolled to athickness of 0.30 mm. Then, the sheet was annealed at 850° C. in a wethydrogen for 5 minutes, from which four square sheets having l=150 mmand W=50 mm were cut out as A1, A2, A3, A4. Next, only A3, A4 weresubjected to an annealing at 970° C. in dry N₂ for 1 minute.

The same procedure as in Example 29 was repeated to obtain the followingresults.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.007   0.95                                                     A2-B2        2.005   0.97                                                     A3-B3        2.003   0.94                                                     A4-B4        2.004   0.93                                                     ______________________________________                                    

Example 34

An ingot of silicon steel comprising C: 0.030%, Si: 3.42%, Mn: 0.25%, S:0.010%, sol Al: 0.027%, N: 0.0091% and the balance being Fe andinevitable impurities was heated at 1350° C. and hot rolled to athickness of 0.50 mm. Then, the sheet was cold rolled to a thickness0.23 mm, from which four square sheets having l=150 mm and W=50 mm werecut out as A1, A2, A3, A4. Next, only A3, A4 were subjected to primaryrecrystallization annealing at 850° C. in a wet H₂ for 2 minutes.

The same procedure as in Example 29 was repeated by using saturatedwater of MgO as a separator to obtain the following results.

    ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A1-B1        2.007   0.81                                                     A2-B2        2.008   0.80                                                     A3-B3        2.006   0.79                                                     A4-B4        2.009   0.81                                                     ______________________________________                                    

Example 35

Molten steel comprising C: 0.079%, Si: 3.25%, Mn: 0.073%, S: 0.012%, solAl: 0.025%, N: 0.0089% and the balance being Fe and inevitableimpurities was slantly cast to a thickness of 150 from 1600° C. in awater-cooled copper mold, quenched to 1150° C., held at the same timefor 5 minutes and immediately hot rolled to a thickness of 2.5 mm.

Then, the sheet was hot rolled to a thickness of 0.22 mm, from which asteel sheet having a length of 150 mm and a width of 100 mm was cut out.Next, the sheet was heated from 200° C. to 700° C. at a temperaturerising rate of 20° C./h and subjected to decarburization annealing at820° C. in a wet hydrogen for 3 minutes to obtain a sheet material.

On the other hand, a single crystal plate comprising Si: 3.0% and thebalance being Fe and inevitable impurities and having a thickness of0.22 mm, a length of 150 mm, a width of 5 mm, α=0° and β=2° was providedas a seed plate.

Then, one-side end portion of the rolling face of the treating sheet ata width of 5 mm in longitudinal direction and one-side full rolling faceof the seed plate were finished into a mirror surface of Ra<0.1 μm bygrinding and polishing.

Next, In of 1 μm in thickness was plated onto the mirrored surface ofthe seed plate, while Sn of 1 μm in thickness was plated onto themirrored surface of the treating sheet. These plated surfaces wereclosed by rubbing so as to coincide the longitudinal directions andjoined by heating in a dry N₂ while a compressive stress: 7 g/mm² wasapplied to the joint face and a supersonic wave was applied.

After MgO containing 1.7% of SnSO₄ was applied as a separator, thejoined body was heated in a dry N₂ by feeding into an annealing furnacehaving a temperature gradient of 1° C./cm between 1150°˜900° C. at afeeding rate of 5 mm/h while holding the treating sheet at lowtemperature side and the seed plate at high temperature side. Then, thebody was subjected to purification annealing at 1200° C. in H₂ for 20hours and a tension coating was applied thereto. As a result, themagnetic properties of the treating sheet were B₈ =2.01 (T) andW_(17/50) =0.69 (W/kg).

Example 36

Molten sheet having the same composition as in Example 35 was cast to athickness of 25 from 1600° C. in a horizontal thin slab casting machine,quenched to 950° C., held at this temperature for 3 minutes andimmediately hot rolled to a thickness of 0.35 mm, which was held at 550°C. for 24 hours and cooled. Then, a steel sheet having a length of 150mm and a width of 100 mm was cut out therefrom and heated from 200° C.to 700° C. at a temperature rising rate of 20° C./h and subjected todecarburization annealing at 820° C. in a wet hydrogen for 5 minutes toobtain a treating sheet.

Then, the same procedure as in Example 35 was repeated to obtain B₈=2.01 (T) and W_(17/50) =0.96 (W/kg).

Example 37

Molten sheet having the same composition as in Example 35 was slantlycast to a thickness of 5 mm from 1600° C. in a water-cooled copper mold,quenched up to 600° C. and immediately warm rolled to a thickness of0.22 mm. Then, a steel sheet having a length of 150 mm and a width of100 mm was cut out therefrom, heated from 200° C. to 700° C. at atemperature rising rate of 20° C./h and then subjected todecarburization annealing at 820° C. in a wet hydrogen for 3 minutes toobtain a treating sheet.

Then, the same procedure as in Example 35 was repeated to obtain B₈=2.00 (T) and W_(17/50) =0.68 (W/kg).

Example 38

A thin sheet of 350 μm in thickness was made by directly cooling frommolten steel comprising C: 0.028%, Si: 3.12%, Mn: 0.075%, S: 0.012%, solAl: 0.019%, N: 0.0095% and the balance being Fe and inevitableimpurities. This thin sheet was immediately warm rolled to a thicknessof 0.20 mm by heating to 550° C., which was held at this temperature for24 hours and cooled. Then, a steel sheet having a length of 150 mm and awidth of 100 mm was cut out therefrom, heated from 200° C. to 700° C. ata temperature rising rate of 20° C./h and subjected to decarburizationannealing at 820° C. in a wet hydrogen for 3 minutes to obtain atreating sheet.

Then, the same procedure as in Example 35 was repeated to obtain B₈=2.01 (T) and W_(17/50) =0.65 (W/kg).

Example 39

An ingot of silicon steel comprising C: 0.075%, Si: 2.85%, Mn: 0.065%,S: 0.014%, sol Al: 0.025%, N: 0.0087% and the balance being Fe andinevitable impurities was heated at 1350° C. and hot rolled to athickness of 1.6 mm. Then, the sheet was annealed at 1130° C. for 2minutes, cold rolled at a reduction of 60% in the same direction as inthe hot rolling direction and then rolled in a direction perpendicularthereto a thickness 0.23 mm. Next, two square sheets having a length of200 mm and a width of 150 were cut out therefrom and decarburized at750° C. in a wet hydrogen for 1 hour as A1, A2.

On the other hand, two single crystal plates having the same compositionas in the hot rolled sheet, a thickness: 0.23 mm, a length: 200 mm and awidth: 5 mm, in which plate face was (100) face and lengthwise directionwas [001] orientation, were provided as B1, B2.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface of Ra<0.1 μm Emery polishing, chemicalpolishing and ion etching. Next, the mirrored surfaces of A1 and B1 aswell as A2 and B2 were closed and heated in N₂ having a dew point of-25° C. by feeding into a temperature tilting furnace having atemperature gradient of 5° C./cm between 1150° C.˜900° C. at a feedingrate of 10 mm/h while a compressive stress: 8 g/mm² was applied to thejoint face in case of A1 and B1 but was not applied in case of A2 and B2and holding A at low temperature side and B at high temperature side.

After MgO was applied as a separator, the joined body was subjected topurification annealing at 1200° C. in H₂ for 20 hours.

The magnetic properties of the thus obtained joined bodies are shown inTable 16.

                  TABLE 16                                                        ______________________________________                                        Presence or absence                                                                        B.sub.10 (T)  W.sub.17/50 (W/kg)                                 of load      presence absence  presence                                                                             absence                                 ______________________________________                                        Magnetization in                                                                           2.00     1.97     1.41   1.49                                    the same direction                                                            as in hot rolling                                                             direction                                                                     Magnetization in                                                                           2.01     1.98     1.39   1.47                                    direction per-                                                                pendicular to hot                                                             rolling direction                                                             ______________________________________                                    

As seen from the above table, the magnetic properties in both the hotrolling direction and the direction perpendicular thereto were verygood.

Example 40

An ingot of silicon steel comprising C: 0.085%, Si: 3.00%, Mn: 0.080%,S: 0.015%, Sol Al: 0.030%, N: 0.0085% and the balance being Fe andinevitable impurities was heated at 1350° C. and hot rolled to athickness of 0.35 mm. Then, two square sheets having a length of 150 mmand a width of 150 were cut out therefrom and decarburized at 750° C. ina wet hydrogen for 3 hours as A3, A4.

On the other hand, two single crystal plates having the same compositionas in the hot rolled sheet, a thickness: 0.35 mm, a length: 150 mm and awidth: 5 mm, in which plate face was (100) face and lengthwise directionwas [001] orientation, were provided as B3, B4.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface of Ra<0.1 μm Emery polishing, chemicalpolishing and ion etching. Next, the mirrored surfaces of A and B wereclosed and heated from 900° C. to 1200° C. at a temperature rising rateof 5° C./h under vacuum of 10⁻⁸ Torr. After MgO was applied as aseparator, the joined body was purification annealing at 1200° C. in H₂for 20 hours and then the magnetic properties of A were measured toobtain results shown in the Table 17.

                  TABLE 17                                                        ______________________________________                                        Presence or absence                                                                        B.sub.10 (T)  W.sub.17/50 (W/kg)                                 of load      presence absence  presence                                                                             absence                                 ______________________________________                                        Magnetization in                                                                           2.01     1.99     1.63   1.69                                    the same direction                                                            as in hot rolling                                                             direction -Magnetization in                                                                2.02     1.98     1.57   1.72                                    direction per-                                                                pendicular to hot                                                             rolling direction                                                             ______________________________________                                    

Example 41

There were provided three sets of A and B polished into mirror surfacein the same manner as in Example 39. After S, Sb or Cu of 0.5 μm wasformed onto the mirrored surface of each set by ion coating, the coatedsurfaces of each set were closed with each other and heated from 1000°C. to 1200° C. at a temperature rising rate of 5° C./h in N₂. After MgOwas applied as a separator, the joined body was subjected topurification annealing at 1200° C. in H₂ for 20 hours.

The magnetic properties of each A portion of the thus obtained joinedbodies are shown in Table 18.

                  TABLE 18                                                        ______________________________________                                               Magnetization in                                                                            Magnetization in                                                the same direction                                                                          direction perpen-                                               as in hot rolling                                                                           dicular to hot                                                  direction     rolling direction                                               B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                                                        B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                           ______________________________________                                        S coating                                                                              2.01    1.62        2.00  1.60                                       Sb coating                                                                             2.00    1.65        2.01  1.59                                       Cu coating                                                                             2.02    1.60        2.00  1.63                                       ______________________________________                                    

As seen from the above table, the magnetic properties in both the hotrolling direction and the direction perpendicular there were very good.

Example 42

An ingot of silicon steel having the same composition as in Example 39was heated to 1350° C. and hot rolled to a thickness of 0.35 mm. Then,two square sheets having a length of 200 mm and a width of 150 mm werecut out therefrom and decarburized at 750° C. in a wet hydrogen for 1hour as A5, A6.

On the other hand, two single crystal plates having the same compositionas in the above hot rolled sheet, a thickness: 0.35 mm, a length: 200 mmand a width: 5 mm, in which plate face was (100) face and lengthwisedirection was [001] orientation, were provided as B5, B6.

Then, one-side end portion of the rolling face of A at a width of 5 mmin longitudinal direction and one-side full rolling face of B werefinished into a mirror surface of Ra<0.1 μm by Emery polishing andchemical polishing. Next, after Sn of 0.5 μm was formed onto eachmirrored surface by ion coating, the coated surfaces of A5 and B5 aswell as A6 and B6 were closed with each other, which were heated in N₂having a dew point of -10° C. by feeding into a temperature tiltingfurnace having a temperature gradient of 5° C./cm between 1150° C.˜900°C. at a feeding rate of 10 mm/h while applying a compressive stress of 7g/mm² to the joint face in case of A5 and B5 but not applying thereto incase of A6 and B6 and holding A at low temperature side and B at hightemperature side.

After MgO was applied as a separator, the joined body was subjected topurification annealing at 1200° C. in H₂ for 20 hours and the magneticproperties were measured to obtain results as shown in Table 19.

                  TABLE 19                                                        ______________________________________                                        Presence or absence                                                                        B.sub.10 (T)  W.sub.17/50 (W/kg)                                 of load      presence absence  presence                                                                             absence                                 ______________________________________                                        Magnetization in                                                                           2.03     1.99     1.55   1.63                                    the same direction                                                            as in hot rolling                                                             direction                                                                     Magnetization in                                                                           2.02     2.00     1.60   1.61                                    direction per-                                                                pendicular to hot                                                             rolling direction                                                             ______________________________________                                    

Thus, the magnetic properties in both the hot rolling direction and thedirection perpendicular thereto were very good.

Example 43

An ingot of silicon steel comprising C: 0.025%, Si: 3.30%, Mn: 0.075%,S: 0.020%, sol Al: 0.020%, N: 0.0095% and the balance being Fe andinevitable impurities was heated to 1350° C. and hot rolled to athickness of 0.5 mm. Then, the sheet was subjected to decarburizationannealing at 700° C. in a wet hydrogen for 3 hours. From the annealedsheet were cut out two square specimens having a length of 300 mm and awidth of 35 mm as A having a lengthwise direction same as in the hotrolling direction and B having a lengthwise direction perpendicularthereto.

On the other hand, two single crystal plates having the same compositionas in the above hot rolled sheet, a thickness: 0.50 mm, a length: 280 mmand a width: 5 mm, in which plate face was (100), were provided as seedplates C.

Then, sectional faces of A and B parallel to the lengthwise directionand perpendicular to the rolling face as well as (100) face of Cperpendicular to plate face were finished into a mirror surface ofRa<0.2 μm by Emery polishing. After Sn of 0.5 μm in thickness wasdeposited onto the treated surfaces, the Sn deposited surfaces as a setof A and C, B and C were closed with each other and joined by rubbingwhile supersonic wave was applied, which was heated in a dry N₂atmosphere by feeding into a temperature tilting furnace having atemperature gradient of 5° C./cm between 1150° C.˜850° C. at a feedingrate of 10 mm/h while applying a compressive stress of 10 g/mm² to thejoint face and holding A, B at low temperature side and C at hightemperature side.

After MgO was applied as a separator, the joined body was subjected topurification annealing at 1200° C. in H₂ for 20 hours and the magneticproperties as shown in Table 20.

                  TABLE 20                                                        ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A-C          2.02    1.95                                                     B-C          2.00    1.88                                                     ______________________________________                                    

Thus, the magnetic properties in both the hot rolling direction and thedirection perpendicular thereto were very good.

Example 44

An ingot of silicon steel having the same composition as in Example 43was heated to 1350° C. and hot rolled to a thickness of 1.15 mm. Then,the sheet was cold rolled at a reduction of 60% in the same direction asin the hot rolling direction and further at a reduction of 50% in adirection perpendicular thereto to obtain a thickness of 0.23 mm.

Then, the sheet was subjected to decarburization annealing at 820° C. ina wet hydrogen for 10 minutes. From the annealed sheet were cut out twosquare specimens having a length of 300 mm and a width of 35 mm as Dhaving a lengthwise direction same as in the hot rolling direction and Ehaving a lengthwise direction perpendicular thereto.

On the other hand, two single crystal plates having the same compositionas in the above hot rolled sheet, a thickness: 0.23 mm, a length: 280 mmand a width: 5 mm, in which plate face was (100), were provided as seedplates F.

Then, the same procedure as in Example 39 was repeated and the magneticproperties of the thus obtained joined bodies were measured to obtainresults as shown in Table 21.

                  TABLE 21                                                        ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        D-F          2.01    1.42                                                     E-F          1.99    1.35                                                     ______________________________________                                    

The magnetic properties in both the hot rolling direction and thedirection perpendicular thereto were very good as in Example 39.

Example 45

An ingot of silicon steel having the same composition as in Example 43was heated to 1250° C. and hot rolled to a thickness of 0.30 mm.

Then, the magnetic properties of the joined body obtained by repeatingthe same procedure as in Example 43 are shown in Table 22.

                  TABLE 22                                                        ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A-C          2.020   1.047                                                    B-C          2.015   1.045                                                    ______________________________________                                    

Example 46

An ingot of silicon steel comprising C: 0.175%, Si: 3.0%, Mn: 0.040%,Se: 0.010%, sol Al: 0.055%, N: 0.0105% and the balance being Fe andinevitable impurities was heated to 1225° C. and hot rolled to athickness of 0.30 mm, from which were then cut out two square specimenshaving a length of 300 mm and a width of 35 mm as A having a lengthwisedirection same as in the hot rolling direction and B having a lengthwisedirection perpendicular thereto. These specimens were subjected todecarburization annealing at 750° C.

Then, the magnetic properties of the joined body obtained by repeatingthe same procedure as in Example 43 are shown in Table 23.

                  TABLE 23                                                        ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A-C          2.010   1.30                                                     B-C          2.017   1.35                                                     ______________________________________                                    

Example 47

An ingot of silicon steel comprising C: 0.205%, Si: 4.2%, Mn: 0.050%, S:0.012%, sol Al: 0.060%, N: 0.0110% and the balance being Fe andinevitable impurities was heated to 1225° C. and hot rolled to athickness of 0.35 mm.

Then, the magnetic properties of the joined body obtained by repeatingthe same procedure as in Example 43 are shown in Table 24.

                  TABLE 24                                                        ______________________________________                                                   B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                           ______________________________________                                        A-C          1.967   1.42                                                     B-C          1.970   1.47                                                     ______________________________________                                    

Example 48

An ingot of silicon steel having the same composition as in Example 43was heated to 1325° C. and hot rolled to a thickness of 1.15 mm. Then,the sheet was subjected to decarburization annealing at 725° C. in a wethydrogen for 10 hours. Then, the sheet was cold rolled at a reduction of60% in the same direction as in the hot rolling direction and further ata reduction of 50% in a direction perpendicular thereto to obtain athickness of 0.23 mm, from which were provided four square specimens ofl=150 mm and w=50 mm having a lengthwise direction (l) same as in thehot rolling direction as A1, A2, and having a lengthwise directionperpendicular thereto as B1, B2. Only A2 and B2 were annealed at 800° C.in a dry H₂ for 2 minutes.

On the other hand, four single crystal plates each comprising Se: 3.0%and the balance being Fe and inevitable impurities and having athickness: 0.23 mm, a length: 150 mm and a width: 5 mm, in which plateface and lengthwise direction were shifted by 2° from (100) face and[001] axis, respectively, were provided as C1, C2, C3, C4.

Then, one-side end portion of the rolling faces of A1, A2, B1, B2 at awidth of 5 mm in longitudinal direction and one-side full rolling facesof C1, C2, C3, C4 were finished into a mirror surface of Ra<0.1 μm byEmery polishing, chemical polishing and ion sputtering. After Sn of 1 μmwas formed onto the mirrored surfaces of C1, C2, C3, C4 by ion coating,the mirrored surface and the coated surface of A1 and C1, A2 and C2, B1and C3, B2 and C4 were closed with each other so as to coincide thelengthwise directions and heated in N₂ having a dew point of -10° C. byfeeding into a temperature tilting furnace having a temperature gradientof 5° C./cm between 1150° C.˜900° C. while applying a compressivestress: 7 g/mm² to the joint face and also applying a supersonic wavethereto and holding A and B at low temperature side and C at hightemperature side.

After MgO was applied as a separator, the joined body was subjected topurification annealing at 1200° C. in H₂ for 20 hours and a tensioncoating was applied thereto, and the magnetic properties were measuredto obtain results as shown in Table 25.

                  TABLE 25                                                        ______________________________________                                                    B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                          ______________________________________                                        A1-C1         2.015   0.84                                                    A2-C2         2.010   0.88                                                    B1-C3         2.013   0.85                                                    B2-C4         2.018   0.87                                                    ______________________________________                                    

Thus, when decarburization was carried out before the rolling, even ifdecarburization annealing was omitted before the finish annealing or theannealing atmosphere was dry H₂, good magnetic properties were obtained.Furthermore, the considerable improvement of magnetic properties hadbeen achieved by slightly shifting (110) face from the rolling face.

Example 49

An ingot of silicon steel comprising C: 0.005%, Si: 3.2%, Mn: 0.10%, S:0.005%, N: 0.0080%, sol Al: 0.032%, and the balance being Fe andinevitable impurities was heated to 1180° C. and hot rolled to athickness of 0.30 mm from which were provided four square specimens ofl=150 mm and w=50 mm having a lengthwise direction (l) same as in thehot rolling direction as A1, A2, and having a lengthwise directionperpendicular thereto as B1, B2. Only A2 and B2 were annealed at 850° C.in dry H₂ for 1 minute.

Then, the same procedure as in Example 48 was repeated to obtain theresults shown in Table 26.

                  TABLE 26                                                        ______________________________________                                                    B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                          ______________________________________                                        A1-C1         2.017   0.98                                                    A2-C2         2.015   1.02                                                    B1-C3         2.021   0.97                                                    B2-C4         2.018   1.01                                                    ______________________________________                                    

Example 50

An ingot of silicon steel comprising C: 0.004%, Si: 3.10%, Mn: 0.052%,S: 0.011%, N: 0.0085%, sol Al: 0.045% and the balance being Fe andinevitable impurities was heated to 1250° C. and hot rolled to athickness of 2.3 mm. Then, the sheet was annealed at 900° C. in a dry N₂for 3 hours and subjected to a combination of cold rollings in the samedirection as in the hot rolling direction and in a directionperpendicular thereto to obtain a thickness of 0.30 mm, from which wereprovided four square specimens of l=150 mm and w=50 mm having alengthwise direction (l) same as in the hot rolling direction A1, A2,and having a lengthwise direction perpendicular thereto as B1, B2. OnlyA2 and B2 were annealed at 975° C. in dry H₂ for 1 minute.

Then, the same procedure as in Example 48 was repeated to obtain theresults shown in Table 27.

                  TABLE 27                                                        ______________________________________                                                  B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                            ______________________________________                                        A1-C1       2.015   0.98                                                      A2-C2       2.025   0.97                                                      B1-C3       2.012   1.01                                                      B2-C4       2.027   0.96                                                      ______________________________________                                    

Example 51

An ingot of silicon steel comprising C: 0.040%, Si: 3.15%, Mn: 0.050%,S: 0.008%, N: 0.0095%, sol Al: 0.042% and the balance being Fe andinevitable impurities was heated to 1200° C. and hot rolled to athickness of 2.3 mm. Then, the sheet was subjected to decarburizationannealing at 850° C. in a wet hydrogen for 10 minutes, and cold rolledto a thickness of 1.15 mm. Further, the sheet was annealed at 850° C. ina wet hydrogen for 10 minutes and subjected to a combination of coldrollings in the same direction as in the hot rolling direction and in adirection perpendicular thereto to obtain a thickness of 0.2 mm, fromwhich were provided four square specimens of l=150 mm and w=50 mm havinga lengthwise direction (l) same as in the hot rolling direction A1, A2,and having a lengthwise direction perpendicular thereto as B1, B2. OnlyA2 and B2 were annealed at 950° C. in dry H₂ for 1 minute.

Then, the same procedure as in Example 48 was repeated to obtain theresults shown in Table 28.

                  TABLE 28                                                        ______________________________________                                                  B.sub.10 (T)                                                                        W.sub.17/50 (W/kg)                                            ______________________________________                                        A1-C1       2.011   0.79                                                      A2-C2       2.022   0.77                                                      B1-C3       2.013   0.76                                                      B2-C4       2.025   0.75                                                      ______________________________________                                    

Example 52

An ingot of silicon steel comprising C: 0.018%, Si: 3.25%, Mn: 0.065%,S: 0.013%, sol Al: 0.018%, N: 0.0085% and the balance being Fe andinevitable impurities was heated to 1350° C. and hot rolled to athickness of 0.35 mm. Then, a square sheet having a length of 150 mm anda width of 150 mm was cut out therefrom as a treating sheet.

On the other hand, a single crystal plate having the same composition asin the above hot rolled sheet, a thickness: 0.30 mm, a length: 150 mmand a width: 5 mm, in which plate face was (100) face and lengthwisedirection was [001] axis, was provided as a seed plate.

Then, one-side end portion of the rolling face of the treating sheet ata width of 5 mm and one-side full rolling face of the seed plate werefinished into a mirror surface of Ra<0.1 μm by Emery polishing, chemicalpolishing and ion etching. Next, the mirrored surfaces of the treatingmaterial and the seed material were closed with each other and heatedfrom 900° C. to 1200° C. at a temperature rising rate of 5° C./h undervacuum of 10⁻⁸ Torr while applying a supersonic wave. After MgO appliedas a separator, the joined body was subjected to purification annealingat 1200° C. in H₂ for 20 hours and the magnetic properties of thetreating material were measured to obtain results as shown in Table 29.

                  TABLE 29                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.62                                                   direction                                                                     Direction per- 2.01    1.58                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 53

An ingot of silicon steel having the same composition as in Example 52was heated to 1350° C. and hot rolled to a thickness of 2.2 mm. Then,the sheet was cold rolled at a reduction of 60% in the same direction asin the hot rolling direction and further rolled in a directionperpendicular thereto to obtain a thickness of 0.23 mm. Next, a squaresheet having a length of 150 mm and a width of 150 mm was cut outtherefrom as a treating sheet.

Then, the magnetic properties of the treating sheet obtained byrepeating the same procedure as in Example 52 are shown in Table 30.

                  TABLE 30                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.40                                                   direction                                                                     Direction per- 2.00    1.38                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 54

An ingot of silicon steel having the same composition as in Example 52was heated to 1200° C. and hot rolled to a thickness of 0.35 mm. Then, asquare sheet having a length of 150 mm and a width of 150 mm was cut outtherefrom as a treating sheet.

Then, the magnetic properties of the treating sheet obtained byrepeating the same procedure as in Example 52 are shown in the followingtable.

                  TABLE 31                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.61                                                   direction                                                                     Direction per- 2.01    1.59                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 55

An ingot of silicon steel comprising C: 0.005%, Si: 3.00%, Mn: 0.045%,S: 0.011%, sol Al: 0.015%, N: 0.0080% and the balance being Fe andinevitable impurities was heated to 1220° C. and hot rolled to athickness of 2.2 mm. Then, the sheet was cold rolled at a reduction of60% in the same direction as in the hot rolling direction and furtherrolled in a direction perpendicular thereto to obtain a thickness of0.23 mm. Next, a square sheet having a length of 150 mm and a width of150 mm was cut out therefrom as a treating sheet.

Then, the magnetic properties of the treating material obtained byrepeating the same procedure as in Example 52 are shown in the followingtable.

                  TABLE 32                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.41                                                   direction                                                                     Direction per- 2.01    1.37                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 56

An ingot of silicon steel comprising C: 0.075%, Si: 3.25%, Mn: 0.042%,S: 0.013%, sol Al: 0.017%, N: 0.0088% and the balance being Fe andinevitable impurities was heated to 1225° C. and hot rolled to athickness of 0.35 mm. Then, a square sheet having a length of 150 mm anda width of 150 mm was cut out therefrom and decarburized at 750° C. in awet hydrogen for 3 hours as a treating material.

Then, the magnetic properties of the treating material obtained byrepeating the same procedure as in Example 52 are shown in Table 33.

                  TABLE 33                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.60                                                   direction                                                                     Direction per- 2.01    1.62                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 57

An ingot of silicon steel having the same composition as in Example 56was heated to 1225° C. and hot rolled to a thickness of 2.2 mm. Then,the sheet was cold rolled at a reduction of 60% in the same direction asin the hot rolling direction and further rolled in a directionperpendicular thereto to obtain a thickness of 0.23 mm. Next, a squaresheet having a length of 150 mm and a width of 150 mm was cut outtherefrom, heated from 200° C. to 700° C. at a rate of 50° C./h anddecarburized at 750° C. in a wet hydrogen for 1 hour as a treatingsheet.

Then, the magnetic properties of the treating sheet obtained byrepeating the same procedure as in Example 52 are shown in Table 34.

                  TABLE 34                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.39                                                   direction                                                                     Direction per- 1.99    1.41                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 58

An ingot of silicon steel having the same composition as in Example 56was heated to 1225° C. and hot rolled to a thickness of 1.15 mm. Then,the sheet was subjected to decarburization annealing at 750° C. in a wethydrogen for 5 hours. Further, it was cold rolled at a reduction of 60%in the same direction as in the hot rolling direction and further rolledin a direction perpendicular thereto to obtain a thickness of 0.23 mm.Next, a square sheet having a length of 150 mm and a width of 150 mm wascut out therefrom as a treating sheet.

Then, the magnetic properties of the treating sheet obtained byrepeating the same procedure as in Example 52 are shown in Table 35.

                  TABLE 35                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.40                                                   direction                                                                     Direction per- 2.00    1.41                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 59

An ingot of silicon steel comprising C: 0.024%, Si: 3.10%, Mn: 0.072%,S: 0.015%, sol Al: 0.022%, N: 0.0079% and the balance being Fe andinevitable impurities was heated to 1350° C. and hot rolled to athickness of 0.34 mm. Then, a square sheet having a length of 150 mm anda width of 150 mm was cut out therefrom as a treating sheet.

On the other hand, a single crystal plate comprising Si: 3.0% and thebalance being Fe and inevitable impurities and having a thickness: 0.23mm, a length: 150 mm and a width: 5 mm, in which plate face was (100)and lengthwise direction was [001] axis, was provided as a seed plate.

Then, one-side end portion of rolling face of the treating sheet at awidth of 5 mm in lengthwise direction and one-side full rolling face ofthe seed plate were finished into a mirror surface of Ra<0.1 μm bygrinding and polishing. After In of 2 μm in thickness was plated ontothe mirror surface of the seed material, the plated surface was closedwith the mirror surface of the treating sheet so as to coincide thelengthwise directions and joined by heating in a dry N₂ through theapplication of supersonic wave while a compressive load: 7 g/mm² wasapplied to the joint face.

After Al₂ O₃ containing 15% of SrSO₄ was applied as a separator, thejoined body was heated in a dry N₂ by feeding into a temperature tiltingfurnace having a temperature gradient of 5° C./cm between 1150°˜900° C.at a feeding rate of 10 mm/h while holding the treating sheet at lowtemperature side and the seed plate at high temperature side.

Then, it was subjected to purification annealing at 1200° C. in H₂ for20 hours and a tension coating was applied thereto, and then themagnetic properties were measured to obtain results as shown in Table36.

                  TABLE 36                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.10                                                   direction                                                                     Direction per- 2.00    1.15                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 60

An ingot of silicon steel having the same composition as in Example 59was heated at 1350° C. and hot rolled to a thickness of 2.2 mm. Then,the sheet was cold rolled at a reduction of 60% in the same direction asin the hot rolling direction and further rolled in a directionperpendicular thereto to a thickness of 0.22 mm. Next, a square sheethaving a length of 150 mm and a width of 150 mm was cut out therefrom asa treating sheet.

Then, the same procedure as in Example 59 was repeated to obtain resultsas shown in Table 37.

                  TABLE 37                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    0.90                                                   direction                                                                     Direction per- 1.99    0.95                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 61

An ingot of silicon steel comprising C: 0.005%, Si: 3.25%, Mn: 0.075%,S: 0.013%, sol Al: 0.015%, N: 0.0085% and the balance being Fe andinevitable impurities was heated to 1225° C. and hot rolled to athickness of 2.2 mm. Then, the sheet was cold rolled at a reduction of60% in the same direction as in the hot rolling direction and furtherrolled in a direction perpendicular thereto to a thickness of 0.22 mm.Then, a square sheet having a length of 150 mm and a width of 150 mm wascut out therefrom as a treating sheet.

On the other hand, a single crystal plate comprising Si: 3.0% and thebalance being Fe and inevitable impurities and having a thickness: 0.22mm, a length: 150 mm and a width: 5 mm, in which plate face was (100)and lengthwise direction was [001] axis, was provided as a seed plate.

Then, one-side end portion of rolling face of the treating sheet at awidth of 5 mm in lengthwise direction was thoroughly degreased andcleaned in a strong alkali solution through the application ofsupersonic wave. On the other hand, one-side full surface of the seedplate was finished into a mirror surface of Ra<0.1 μm by grinding andpolishing. Then, In of 1 μm was plated onto the mirror surface of theseed material, while Sn of 1 μm in thickness was plated onto the cleanedsurface of the treating sheet. These plated surfaces were closed witheach other by rubbing so as to coincide the lengthwise directions andjoined by heating in a dry N₂ through the application of supersonic wavewhile applying a compressive stress: 100 g/mm² to the joint face.

Then, the joined body was coated with an annealing separator and heatedin a dry N₂ by feeding into a temperature tilting furnace having atemperature gradient of 5° C./cm between 1150°˜900° C. at a feeding rateof 10 mm/h while holding the treating sheet at low temperature side andthe seed plate at high temperature side.

Next, it was subjected to purification annealing at 1200° C. in H₂ for20 hours and a tension coating was applied thereto, and then themagnetic properties were measured to obtain results as shown in Table38.

                  TABLE 38                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.15                                                   direction                                                                     Direction per- 2.00    1.13                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 62

An ingot of silicon steel comprising C: 0.045%, Si: 3.17%, Mn: 0.074%,S: 0.014%, sol Al: 0.020%, N: 0.0081% and the balance being Fe andinevitable impurities was heated to 1225° C. and hot rolled to athickness of 2.2 mm. Then, the sheet was subjected to decarburizationannealing at 750° C. in a wet hydrogen for 3 hours, cold rolled at areduction of 60% in the same direction as in the hot rolling directionand further rolled in a direction perpendicular thereto to obtain athickness of 0.22 mm. Then, a square sheet having a length of 150 mm anda width of 150 mm was cut out therefrom, heated from 200° C. to 700° C.at a temperature rising rate of 20° C./h and then subjected todecarburization at 820° C. in a wet hydrogen for 3 minutes as a treatingsheet.

On the other hand, a single crystal plate comprising Si: 3.0% and thebalance being Fe and inevitable impurities and having a thickness: 0.22mm, a length: 150 mm and a width: 5 mm, in which plate face was (100)and lengthwise direction was [001] axis, was provided as a seed plate.

Then, one-side end portion of rolling face of the treating sheet at awidth of 5 mm in lengthwise direction and one-side full surface of theseed plate were finished into a mirror surface of surface of Ra<0.1 μmby grinding and polishing. Next, In of 1 μm in thickness and Sn of 1 μmin thickness were plated onto the mirror surface of the seed plate andthe cleaned surface of the treating plate, respectively. These platedsurfaces were closed by rubbing so as to coincide the lengthwisedirections and joined by heating in a dry N₂ through the application ofsupersonic wave while applying a compressive stress: 7 g/mm² to thejoint face.

After MgO containing 1.7% of SrSO₄ was applied as a separator, thejoined body was heated in a dry N₂ by feeding into a temperature tiltingfurnace having a temperature gradient of 1° C./cm between 1150°˜900° C.at a feeding rate of 5 mm/h while holding the treating sheet at lowtemperature side and the seed plate at high temperature side.

Then, it was subjected to purification annealing at 1200° C. in H₂ for20 hours and a tension coating was applied thereto, and then themagnetic properties were measured to obtain results as shown in Table39.

                  TABLE 39                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.08                                                   direction                                                                     Direction per- 1.99    1.11                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 63

Molten steel comprising C: 0.0085%, Si: 3.17%, Mn: 0.070%, S: 0.008%,sol Al: 0.017%, N: 0.0082% and the balance being Fe and inevitableimpurities was slantly cast to a thickness of 150 mm from 1600° C. in awater-cooled copper mold, quenched to 1150° C., held at this temperaturefor 5 minutes and immediately hot rolled to a thickness of 2.5 mm.

Then, the sheet was cold rolled at a reduction of 60% in the samedirection as in the hot rolling direction and further rolled in adirection perpendicular thereto to obtain a thickness of 0.22 mm. Next,a square sheet having a length of 150 mm and a width of 150 mm was cutout therefrom, heated from 200° C. to 700° C. at a temperature risingrate of 20° C./h and then subjected to decarburization at 820° C. in awet hydrogen for 5 minutes as a treating sheet.

Then, the same procedure as in Example 61 was repeated to obtain theresults shown in Table 40.

                  TABLE 40                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.01    1.12                                                   direction                                                                     Direction per- 2.01    1.15                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 64

Molten steel having the same composition as in Example 63 was cast to athickness of 25 mm from 1600° C. in a horizontal thin slab castingmachine, quenched to 950° C., held at this temperature for 3 minutes andimmediately hot rolled to a thickness of 0.35 mm, which was held at 550°C. for 24 hours and cooled. Then, a square sheet having a length of 150mm and a width of 150 mm was cut out therefrom and subjected todecarburization annealing at 750° C. for 1 hour as a treating sheet.

Then, the same procedure as in Example 61 was repeated to obtain theresults shown in Table 41.

                  TABLE 41                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.61                                                   direction                                                                     Direction per- 2.01    1.55                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 65

Molten steel having the same composition as in Example 63 was slantlycast to a thickness of 5 mm from 1600° C. in a water-cooled copper mold,quenched to 600° C. and immediately warm rolled to a thickness of 0.22mm. Then, a square sheet having a length of 150 mm and a width of 150 mmwas cut out therefrom, heated from 200° C. to 700° C. at a temperaturerising rate of 20° C./h and then subjected to decarburization annealingat 820° C. in a wet hydrogen for 5 minutes as a treating sheet.

Then, the same procedure as in Example 61 was repeated to obtain theresults shown in Table 42.

                  TABLE 42                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.13                                                   direction                                                                     Direction per- 2.01    1.14                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 66

A thin ribbon of 3500 μm in a thickness was made by direct quenchingfrom molten steel comprising C: 0.025%, Si: 3.5%, Mn: 0.072%, S: 0.009%,sol Al: 0.017%, N: 0.0085% and the balance being Fe and inevitableimpurities. This thin ribbon was warm rolled to a thickness of 0.20 mmwhile heating to 550° C., which was held for 24 hours and cooled. Then,a square sheet having a length of 150 mm and a width of 150 mm was cutout therefrom, heated from 200° C. to 700° C. at a temperature risingrate of 20° C./h and then subjected to decarburization at 820° C. in awet hydrogen for 3 minutes as a treating sheet.

Then, the same procedure as in Example 61 was repeated to obtain theresults shown in Table 43.

                  TABLE 43                                                        ______________________________________                                        Magnetization                                                                 direction      B.sub.10 (T)                                                                          W.sub.17/50 (W/kg)                                     ______________________________________                                        Hot rolling    2.00    1.10                                                   direction                                                                     Direction per- 2.01    1.11                                                   pendicular to                                                                 hot rolling                                                                   ______________________________________                                    

Example 67

An ingot of silicon steel comprising C: 0.065%, Si: 3.25%, Mn: 0.070%,S: 0.018%, P: 0.0080%, sol Al: 01035%, N: 0.0080% and the balance beingFe and inevitable impurities was heated to 1350° C., hot rolled to athickness of 1.9 mm, cold rolled to a thickness of 0.20 mm, heated from200° C. to 700° C. at a temperature rising rate of 20° C./h and thensubjected to decarburization annealing at 820° C. in a wet hydrogen for5 minutes. After an annealing separator of MgO containing 15% or SrSO₄was applied to the thus obtained steel sheet, three coils having athickness of 10 mm, a diameter of 550 mm, 700 mm, 1000 mm and a width of100 mm were prepared as treating coils A, B, C.

In these treating coils, the edge portion of the coil was removed by 0.5mm in widthwise direction of the steel sheet by grinding in a directionperpendicular to the rolling face, and finished into a clean mirrorsurface of Ra<0.2 μm by polishing and sputtering.

On the other hand, a surface of a single crystal plate comprising Si:3.0% and the balance being Fe and inevitable impurities and having alength: 10 mm, a width of 5 mm and a thickness of 0.2 mm, in which (110)face was parallel to plate face and lengthwise direction was [110]orientation, was finished into a clean mirror surface of Ra<0.2 μm bypolishing and argon sputtering as a seed plate D.

Then, the seed plate D was closely joined to the polished surfaces of A,B, C, respectively, at an interval of 20 mm so that the lengthwisedirection of the seed plate was directed toward the center of the coilin the treating materials A, B, C, and then annealed in a vacuum furnaceof 10⁻⁴ Torr at 980° C. for 24 hours while applying a compressive stressof 10 g/mm² to the joint face. After the flattening annealing at 800° C.for 3 hours, the crystal structures of the treating coils A, B, C wereexamined, from which the seed plate D was confirmed to grow into all ofthe treating coils.

In this case, the magnetic flux density B₁₀ at a magnetization force of1000 A/m are shown in Table 44.

                  TABLE 44                                                        ______________________________________                                                  B.sub.10 (T)                                                        ______________________________________                                                A   1.95                                                                      B   1.98                                                                      C   2.01                                                              ______________________________________                                    

As seen from the above Table 44, the larger the coil diameter, theeasier the magnetization and the shifting of orientation from therolling face is less.

Example 68

When the treating coil C and the seed plate D in Example 67 were closelyjoined with each other in the same manner as in Example 67, D wasarranged at an interval of 10 mm, 40 mm, 80 mm to obtain treating coilsC-1, C-2, C-3. Then, these materials were treated in the same manner asin Example 67 as X and in the same manner as in Example 67 except thatthe annealing atmosphere was N₂ having a dew point of -30° C. as Y.

As the crystal structure of each of the thus obtained coils wasexamined, it was observed in the case X that the seed plate D grew inthe treating coil, but the growth was partly observed in the case Y.

The B₁₀ value of each coil are shown in Table 45.

                  TABLE 45                                                        ______________________________________                                                      B.sub.10 (T)                                                                  X    Y                                                          ______________________________________                                        C-1             2.03   1.92                                                   C-2             1.98   1.91                                                   C-3             1.93   1.90                                                   ______________________________________                                    

The B₁₀ value is high in the case X that the atmosphere is vacuum andthe joint face is an activated state as compared with the case Y thatthe atmosphere is oxidizable and the joint face is an inactivated state.Further, as the planting interval of the seed plate becomes shorter, theB₁₀ value becomes higher, which shows that the magnetization is easy andthe shifting of orientation from the rolling face is less.

Example 69

B1, B2 were before and after the annealing in the treating coil B usedin Example 67, respectively edge portions of whose coils were finishedinto a clean mirror surface in the same manner as in Example 67. Then,the coils B1 and B2 were piled one upon the other so as to close themirrored surfaces with each other, which was heated by feeding into atemperature tilting furnace having a temperature gradient of 5° C./cmbetween 1150° C.˜900° C. at a feeding rate of a10 mm/h while holding B1at low temperature side and B2 at high temperature side. Moreover, theinside of the furnace was maintained under vacuum of 10⁻⁴ Torr.

After the flattening annealing at 800° C. for 3 hours, the B₁₀ value ofB1 was measured to be B₁₀ =1.99˜1.98 (T). By continuously planting theseed plate in the circumferential direction of the coil, the high B₁₀value equal to that of the seed plate B2 was obtained at aboutself-weight of the seed plate B2 without particularly applying stress.

Example 70

Three sets of the treating coils B1, B2 used in Example 69 wereprovided. After Sn, Sb, Cu were deposited onto the cleaned mirrorsurfaces of each set at a thickness of 1 μm by sputtering every the set,the coils were piled one upon the other so as to close the depositedsurfaces with each other every the set and joined by heating through theapplication of supersonic wave, which was heated in N₂ having a dewpoint of -30° C. by feeding into a temperature tilting furnace having atemperature gradient of 5° C./cm between 1150° C.˜900° C. while holdingB2 at high temperature side.

After the flattening annealing at 800° C. for 3 hours, the B₁₀ value ofB2 of each set was measured to obtain the results shown in Table 46.

                  TABLE 46                                                        ______________________________________                                                    B.sub.10 (T)                                                      ______________________________________                                        Sn coating    1.98 ˜ 1.99                                               Sb coating    1.97 ˜ 1.99                                               Cu coating    1.96 ˜ 1.98                                               ______________________________________                                    

By joining through the interposition of the insert member, good resultsequal to that of the seed plate B1 were obtained even when the annealingwas carried out in an oxidizing atmosphere.

Example 71

An ingot of iron alloy comprising C: 0.035%, Al: 3.00%, Mn: 0.065%, Se:0.020%, P: 0.008% and the balance being Fe and inevitable impurities washeated to 1350° C., hot rolled to a thickness of 2.3 mm and thensubjected to two-times cold rolling through an intermediate annealing toa thickness of 0.20 mm. Then, the sheet was subjected to decarburizationand primary recrystallization annealing at 820° C. in a wet hydrogen for5 minutes, coated with an annealing separator and wound into a coilhaving a thickness of 10 mm, a diameter of 700 mm and a width of 100 mmas a treating coil E. After the coil edge portion was finished into aclean mirror surface in the same manner as in Example 67, Sn wasdeposited at a thickness of 1 μm by sputtering, which was closed withthe deposited surface of the seed plate B2 in Example 70 having Sn of 1μm in thickness and piled one upon the other and treated in the samemanner as in Example 70.

After the flattening annealing at 800° C. for 3 hours, the orientationsof crystal grains in the treating coil E and the seed plate B2 weremeasured, and as a result, the shifting of orientation from (100)[001]in both was 3° on average and the orientation of the seed plate was welltransferred to the treating coil.

Example 72

An ingot of silicon steel comprising C: 0.059%, Si: 3.35%, Mn: 0.065%,S: 0.015%, sol Al: 0.025%, N: 0.0095% and the balance being Fe andinevitable impurities was heated to 1350° C., hot rolled to a thicknessof 2.2 mm, cold rolled to a thickness of 0.20 mm, heated from 200° C. to700° C. at a temperature rising rate of 20° C./h and subjected todecarburization annealing at 820° C. in a wet hydrogen for 3 minutes.After MgO containing 15% of SrSO₄ was applied to the thus obtained steelsheet as an annealing separator, a coil having a thickness of 10 mm, adiameter of 550 mm and a width of 1000 mm was prepared as treating coil.

After the coil edge portion of the treating material was removed by 0.5mm in the widthwise. direction of the steel sheet through the polishingin a direction perpendicular to the rolling face, it was finished into amirror surface of Ra<0.2 μm by polishing.

On the other hand, a surface of plate-like single crystal comprising Si:3.0% and the balance being Fe and inevitable impurities and having alength: 10 mm, a width: 5 mm and a thickness: 0.2 mm, in which (110)face was parallel to plate face and lengthwise direction was [110]orientation, was finished into a clean mirror surface of Ra<0.2 μm bygrinding and polishing and then coated with Sn of 1 μm in thickness byplating to obtain a seed plate.

Then, the plated surface of the seed plate was closed with the polishedsurface of the treating coil at an interval of 20 mm so that the seedplate was directed toward the center of the coil of the treatingmaterial and joined by heating through the application of supersonicwave of 60 kHz while applying a compressive stress of 10 g/mm² to thejoint face.

Next, the joined body was placed in a usual box furnace and heated to1200° C. to a temperature rising rate of 20° C./h in N₂ while applying acompressive stress of 3 g/mm² to the joint face. After the flatteningannealing at 800° C. for 3 hours, the crystal structure of the treatingcoil was measured, from which it was confirmed that the seed plate grewinto the treating coil.

In this case, the magnetic flux density B₁₀ value at a magnetizationforce of 1000 A/m was B₁₀ =1.97 (T).

Example 73

When the treating coil and seed plate in Example 72 were joined in thesame manner as in Example 72, the joining was carried out under vacuumof 10⁻³ Torr. After the annealing to 1100° C. in N₂ under atmosphericpressure, the heating was again carried out to 1200° C. under vacuum of10⁻³ Torr.

After the flattening annealing at 800° C. for 3 hours, the crystalstructure of the treating coil was measured, from which it was confirmedthat the seed plate grew into the treating coil.

In this case, the magnetic flux density B₁₀ value at a magnetizationforce of 1000 A/m was B₁₀ =1.98 (T).

Example 74

An ingot of silicon steel comprising C: 0.020%, Mn: 0.075%, S: 0.016%,sol Al: 0.021%, N: 0.0090% and the balance being Fe and inevitableimpurities was heated to 1250° C., hot rolled to a thickness of 2.2 mm,cold rolled to a thickness of 0.22 mm, heated from 200° C. to 700° C. ata temperature rising rate of 20° C./h and subjected to decarburizationannealing at 850° C. in a wet hydrogen for 5 minutes. The thus obtainedsteel sheet was subjected to skin-pass rolling to introduce 2% plasticstrain thereinto. After MgO containing 15% of SrSO₄ was applied to thesteel sheet as an annealing separator, a coil having a thickness of 10mm, a diameter of 550 mm and a width of 1000 mm was prepared as atreating coil.

After the coil edge portion of the treating coil was removed by 0.5 mmin the widthwise direction of the steel sheet by grinding in a directionperpendicular to the rolling face, it was finished into a clean mirrorsurface of Ra<0.2 μm by polishing.

On the other hand, a surface of plate-like single crystal comprising Si:2.0% and the balance being Fe and inevitable impurities and having alength: 10 mm, a width: 5 mm and a thickness: 0.2 mm, in which (110)face was parallel to plate face and lengthwise direction was [110]orientation, was finished into a clean mirror surface of Ra<0.2 μm bygrinding and polishing and then coated with Sn of 1 μm in thickness byplating to obtain a seed plate.

Then, the plated surface of the seed plate was closed with the polishedsurface of the treating coil at an interval of 20 mm so that the seedplate was directed toward the center of the treating coil and joined byheating through the application of supersonic wave of 60 kHz whileapplying a compressive stress of 10 g/mm² to the joint face.

Next, the joined body was placed in a usual box furnace and heated in N₂at a maximum temperature not exceeding 910° C. while applying acompressive stress of 3 g/mm² to the joint face. After the flatteningannealing at 800° C. for 3 hours, the crystal structure of the treatingcoil was measured, from which it was confirmed that the seed plate grewinto the treating coil.

In this case, the magnetic flux density B₁₀ value at a magnetizationforce of 1000 A/m was B₁₀ =2.13 (T).

Example 75

Molten steel comprising C: 0.058%, Si: 3.15%, Mn: 0.075%, Sn: 0.015%,sol Al: 0.025%, N: 0.0075% and the balance being Fe and inevitableimpurities was slantly cast to a thickness of 150 mm from 1600° C. in awater-cooled copper mold, quenched to 1150° C., held at this temperaturefor 5 minutes and immediately hot rolled to a thickness of 2.5 mm. Then,the sheet was cold rolled to a thickness of 0.22 mm and heated in Arfrom 200° C. to 700° C. at a temperature rising rate of 20° C./h. Next,the sheet was subjected to decarburization annealing at 820° C. in a wethydrogen for 3 minutes and coated with MgO annealing separatorcontaining MgSO₄ : 1.7%, from which a coil having a thickness of 10 mm,an inner diameter of 550 mm and a width of 1000 mm was prepared as atreating coil.

After the coil edge portion of the treating plate was removed by 0.5 mmin the widthwise direction of the steel sheet by grinding in a directionperpendicular to the rolling face, it was finished into a clean mirrorsurface of Ra<0.2 μm by polishing.

On the other hand, a surface of plate-like single crystal comprising Si:3.0% and the balance being Fe and inevitable impurities and having alength: 10 mm, a width: 5 mm and a thickness: 0.2 mm, in which (110)face was parallel to plate face and lengthwise direction was [110]orientation, was finished into a clean mirror surface of Ra<0.2 μm bygrinding and polishing and then coated with Sn of 2 μm in thickness byplating to obtain a seed plate.

Then, the plated surface of the seed plate was closely joined with thepolished surface of the treating coil at an interval of 20 mm so thatthe seed plate was directed toward the center of the treating coil andheated through the application of supersonic wave while applying acompressive stress of 10 g/mm² to the joint face. The heating wascarried out by supplying heat to the side end portion of the seed platesand raising temperature at a rate of 20° C./h, whereby the temperatureat an end portion opposite to the seed plate was raised to 1100° C.

Next, both the end portions were subjected to purification annealing at1200° C. in hydrogen for 20 hours. The average magnetic property inwidthwise direction of the obtained coil was B₈ =2.00 (T).

Example 76

Molten steel having the same composition as in Example 75 was cast to athickness of 25 mm from 1600° C. in a horizontal thin slab castingmachine, quenched to 950° C., held for 3 minutes and immediately hotrolled to a thickness of 0.35 mm, which was held at 550° C. for 24 hoursand cooled. Then, the steel sheet was subjected to decarburizationannealing at 820° C. in a wet hydrogen for 5 minutes and coated with MgOannealing separator containing SrSO₄ : 1.7%, from which a coil having athickness of 10 mm, an inner diameter of 550 mm and a width of 100 mmwas prepared as a treating coil.

After the coil edge portion of the treating plate was removed by 0.5 mmin the widthwise direction of the steel sheet by grinding in a directionperpendicular to the rolling face, it was finished into a clean mirrorsurface of Ra<0.2 μm by polishing.

On the other hand, a surface of plate-like single crystal comprising Si:3.0% and the balance being Fe and inevitable impurities and having alength: 10 mm, a width: 5 mm and a thickness: 0.2 mm, in which (100)face was parallel to plate face and lengthwise direction was [100]orientation, was finished into a clean mirror surface of Ra<0.2 μm bygrinding and polishing and then coated with In of 2 μm in thickness byplating to obtain a seed plate.

The average magnetic properties in widthwise direction of the coilobtained by the same procedure as in Example 75 were magnetizationproperty in the hot rolling direction B₈ =2.00 (T) and magnetizationproperty in a direction perpendicular to the hot rolling direction B₈=2.01 (T).

Example 77

Molten steel having the same composition as in Example 75 was slantlycast to a thickness of 5 mm from 1600° C. in a water-cooled copper mold,quenched to 600° C. and immediately warm rolled to a thickness of 0.22mm. Then, the sheet was heated in Ar from 200° C. to 700° C. at atemperature rising rate of 20° C./h and subjected to decarburizationannealing at 820° C. in a wet hydrogen for 3 minutes and coated with MgOannealing separator containing 4% of ferromanganese nitride, from whicha coil having a thickness of 10 mm, an inner diameter of 550 mm and awidth of 1000 mm was prepared as a treating coil.

The average magnetic properties in widthwise direction of the coilobtained by the same procedure as in Example 75 was B₈ =2.00 (T).

Example 78

A thin ribbon of 350 μm in a thickness was made by direct quenching frommolten steel comprising C: 0.005%, Si: 4.5%, Mn: 0.080%, S: 0.012%, solAl: 0.015%,. N: 0.0080% and the balance being Fe and inevitableimpurities. This thin ribbon was warm rolled to a thickness of 0.20 mmwhile heating to 550° C., which was held at 550° C. for 24 hours andcooled. Then, the steel sheet was subjected to decarburization annealingat 820° C. in a wet hydrogen for 3 minutes and coated with MgO annealingseparator, from which a coil having a thickness of 10 mm, an innerdiameter of 550 mm and a width of 100 mm was prepared as a treatingcoil.

The average magnetic properties in widthwise direction of the coilobtained by the same procedure as in Example 68 were magnetizationproperty in the hot rolling direction B₈ =2.01 (T) and magnetizationproperty in a direction perpendicular to the hot rolling direction B₈=1.90 (T).

INDUSTRIAL APPLICABILITY

According to the invention, not only the strict control to particularorientation but also the mass production of crystal bodies having suchan orientation are possible, so that the invention largely contributesto the improvement of properties in the product and the yield. Forexample, in grain oriented electromagnetic steel sheets andbidirectional oriented electromagnetic steel sheets, the magnetic fluxdensity can largely be, improved, and particularly <111> axis as ahardly magnetization axis is not included in the rolling face of thebidirectional oriented electromagnetic steel sheet, so that they areuseful as an iron core for rotating bodies and the magnetization atcorner portion of transformers is easy, which contributes toenergy-saving.

Furthermore, according to the invention, the crystalline orientation atcoil unit can be controlled, so that not only the strict control ofcrystalline orientation but also the practical mass production inindustry, which have never been established in the conventionaltechnique, are possible and the invention largely contributes to thestable improvement of properties depending upon the crystallineorientation and the stable supplement of good products.

Moreover, the invention contributes to basic studies on the orientationdependency of properties because crystal bodies of particularorientation are easily obtained, so that it is considered that theinvention largely contributes to the development of the studies.

We claim:
 1. A method of producing grain oriented electromagnetic steelsheets having improved magnetic properties by hot rolling a slab ofsilicon-containing steel, rendering the hot rolled sheet into finalthickness without annealing and cold rolling or through annealing and/orcold rolling at least one time, and then subjecting it to a finishannealing, including a step of joining a recrystallization seed materialon an edge portion of the steel sheet as a treating material at a stepafter the hot rolling and before the finish annealing under a conditionsatisfying the following orientation relationships, in which said seedmaterial is contacted with said steel sheet through an insert memberhaving a melting point lower than those of said seed material and steelsheet, and then heated to a temperature causing grain boundary movementto grow the crystalline orientation of said seed material over a wholeof said steel sheet,

    |α|≦5°

    1≦|β|≦5°

where α: angle defined by a projection line of <001> axis of seedmaterial with respect to rolling face of steel sheet and the rollingdirection of steel sheet; β: inclination angle of <001> axis of seedmaterial with respect to rolling face of steel sheet.
 2. A method ofproducing grain oriented electromagnetic steel sheets having improvedmagnetic properties by hot rolling a slab of silicon-containing steel,rendering the hot rolled sheet into a final thickness without annealingand cold rolling or through annealing and/or cold rolling at least onetime, and then subjecting it to a primary recrystallization annealingand further to a finish annealing, including a step of joining arecrystallization seed material on an edge portion of the steel sheet asa treating material at a step after the hot rolling and before thefinish annealing under a condition satisfying the following orientationrelationships, in which said seed material is contacted with said steelsheet through an insert member having a melting point lower than thoseof said seed material and steel sheet, and then heated to a temperaturecausing grain boundary movement to grow the crystalline orientation ofsaid seed material over a whole of said steel sheet,

    |α|≦5°

    1≦|β|≦5°

where α: angle defined by a projection line of <001> axis of seedmaterial with respect to rolling face of steel sheet and the rollingdirection of steel sheet; β: inclination angle of <001> axis of seedmaterial with respect to rolling face of steel sheet.
 3. The method ofproducing grain oriented electromagnetic steel sheets according to claim1, or 2, wherein C amount in said steel before said cold rolling isreduced to not more than 0.010 wt %.
 4. A method of producingbidirectional oriented electromagnetic steel sheets having improvedmagnetic properties by hot rolling a slab of silicon-containing steel,rendering the hot rolled sheet into a final thickness without annealingand cold rolling or through annealing and/or cold rolling at least onetime and then subjecting it to a finish annealing, including a step ofjoining a recrystallization seed material on an edge portion of thesteel sheet as a treating material at a step after the hot rolling andbefore the finish annealing under a condition satisfying the followingorientation relationships, in which said seed material is contacted withsaid steel sheet through an insert member having a melting point lowerthan those of said seed material and steel sheet, and then heated to atemperature causing grain boundary movement to grow the crystallineorientation of said seed material over a whole of said steel sheet,

    |α|≦10°

    |β|≦10°

where α: angle defined by a projection line of <001> axis of seedmaterial with respect to rolling face of steel sheet and the rollingdirection of steel sheet; β: inclination angle of {100} face of seedmaterial with respect to rolling face of steel sheet.
 5. A method ofproducing bidirectional oriented electromagnetic steel sheets havingimproved magnetic properties by hot rolling a slab of silicon-containingsteel, rendering the hot rolled sheet into a final thickness withoutannealing and cold rolling or through annealing and/or cold rolling atleast one time, and then subjecting it to a primary recrystallizationannealing and further to a finish annealing, including a step of joininga recrystallization seed material on an edge portion of the steel sheetas a treating material at a step after the hot rolling and before thefinish annealing under a condition satisfying the following orientationrelationships, in which said seed material is contacted with said steelsheet through an insert member having a melting point lower than thoseof said seed material and steel sheet, and then heated to a temperaturecausing grain boundary movement to grow the crystalline orientation ofsaid seed material over a whole of said steel sheet,

    |α|≦10°

    |β|≦10°

where α: angle defined by a projection line of <001> axis of seedmaterial with respect to rolling face of steel sheet and the rollingdirection of steel sheet; β: inclination angle of {100} face of seedmaterial with respect to rolling face of steel sheet.
 6. The method ofproducing bidirectional oriented electromagnetic steel sheets accordingto claim 4 or 5, wherein C amount in said steel before said cold rollingis reduced to not more than 0.010 wt %.
 7. The method according toclaims 1, 2, 4, or 5, further comprising:a. selecting a coil-like steelsheet as said treating material; b. selecting a seed material having acrystal structure a) the same as said treating material or b) whichdiffers from said crystal structure of said seed material by havinginterstitial or substitutional elements present in amounts such that thecrystal lattices of said seed material and said treating material differby 30% or less, wherein said seed material has said crystallineorientation at a state of energy lower than that of said treatingmaterial; c. contacting and joining a coiled end face of said coil-likesteel sheet through an insert member having a melting point lower thanthose of said seed material and said treating material, and then heatingto a temperature causing grain boundary movement to produce saidcoil-like steel sheet into a crystal body having said crystallineorientation.
 8. The method according to claims 1, 2, 4 or 5, furthercomprising the step of joining said treating material and said seedmaterial under an application of stress.
 9. The method as in any ofclaims 1, 2, 4 or 5 in which said heating is conducted in anon-oxidizing atmosphere.